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-rwxr-xr-x.ci/patch_for_twisted_trunk.sh8
-rw-r--r--.github/workflows/tests.yml46
-rw-r--r--.github/workflows/twisted_trunk.yml46
-rw-r--r--changelog.d/12213.bugfix1
-rw-r--r--changelog.d/12319.bugfix1
-rw-r--r--changelog.d/12340.doc1
-rw-r--r--changelog.d/12344.removal1
-rw-r--r--changelog.d/12365.feature1
-rw-r--r--changelog.d/12368.doc1
-rw-r--r--changelog.d/12382.removal1
-rw-r--r--changelog.d/12394.misc1
-rw-r--r--changelog.d/12395.misc1
-rw-r--r--changelog.d/12425.misc1
-rw-r--r--changelog.d/12434.misc1
-rw-r--r--changelog.d/12438.misc1
-rw-r--r--changelog.d/12441.misc1
-rw-r--r--changelog.d/12445.misc1
-rw-r--r--changelog.d/12449.misc1
-rw-r--r--changelog.d/12450.misc1
-rw-r--r--changelog.d/12451.doc1
-rw-r--r--changelog.d/12454.misc1
-rw-r--r--changelog.d/12455.misc1
-rw-r--r--changelog.d/12457.doc1
-rw-r--r--changelog.d/12464.misc1
-rw-r--r--changelog.d/12465.feature1
-rw-r--r--changelog.d/12466.misc1
-rw-r--r--changelog.d/12467.misc1
-rw-r--r--changelog.d/12474.misc1
-rw-r--r--changelog.d/12483.misc1
-rwxr-xr-xdebian/build_virtualenv20
-rw-r--r--debian/changelog7
-rw-r--r--debian/clean1
-rw-r--r--docker/Dockerfile-workers17
-rw-r--r--docker/complement/SynapseWorkers.Dockerfile40
-rwxr-xr-xdocker/complement/conf-workers/start-complement-synapse-workers.sh50
-rw-r--r--docker/conf-workers/supervisord.conf.j23
-rwxr-xr-xdocker/configure_workers_and_start.py59
-rw-r--r--docs/SUMMARY.md1
-rw-r--r--docs/code_style.md54
-rw-r--r--docs/systemd-with-workers/README.md10
-rw-r--r--docs/systemd-with-workers/workers/federation_reader.yaml13
-rw-r--r--docs/systemd-with-workers/workers/generic_worker.yaml13
-rw-r--r--docs/upgrade.md7
-rw-r--r--docs/usage/configuration/config_documentation.md3412
-rw-r--r--docs/website_files/table-of-contents.js14
-rw-r--r--docs/workers.md18
-rw-r--r--poetry.lock25
-rwxr-xr-xscripts-dev/lint.sh16
-rwxr-xr-xscripts-dev/release.py3
-rw-r--r--synapse/api/constants.py2
-rw-r--r--synapse/api/filtering.py12
-rw-r--r--synapse/config/experimental.py5
-rw-r--r--synapse/config/server.py8
-rw-r--r--synapse/events/utils.py6
-rw-r--r--synapse/federation/federation_server.py28
-rw-r--r--synapse/federation/transport/client.py10
-rw-r--r--synapse/federation/transport/server/federation.py2
-rw-r--r--synapse/handlers/device.py38
-rw-r--r--synapse/handlers/events.py6
-rw-r--r--synapse/handlers/federation.py75
-rw-r--r--synapse/handlers/federation_event.py39
-rw-r--r--synapse/handlers/message.py19
-rw-r--r--synapse/handlers/presence.py56
-rw-r--r--synapse/handlers/sync.py15
-rw-r--r--synapse/rest/client/login.py9
-rw-r--r--synapse/rest/client/sync.py9
-rw-r--r--synapse/rest/client/versions.py3
-rw-r--r--synapse/server.py2
-rw-r--r--synapse/storage/databases/main/devices.py65
-rw-r--r--synapse/storage/databases/main/events.py20
-rw-r--r--synapse/storage/databases/main/events_worker.py24
-rw-r--r--synapse/storage/databases/main/relations.py78
-rw-r--r--synapse/storage/databases/main/room.py31
-rw-r--r--synapse/storage/databases/main/state.py50
-rw-r--r--synapse/storage/databases/main/stream.py26
-rw-r--r--synapse/storage/persist_events.py56
-rw-r--r--synapse/storage/schema/__init__.py6
-rw-r--r--sytest-blacklist4
-rw-r--r--tests/api/test_filtering.py4
-rw-r--r--tests/federation/test_federation_sender.py51
-rw-r--r--tests/federation/test_federation_server.py41
-rw-r--r--tests/handlers/test_presence.py79
-rw-r--r--tests/rest/admin/test_admin.py1
-rw-r--r--tests/rest/client/test_login.py27
-rw-r--r--tests/rest/client/test_room_batch.py125
-rw-r--r--tests/storage/test_devices.py47
-rw-r--r--tox.ini31
87 files changed, 4462 insertions, 557 deletions
diff --git a/.ci/patch_for_twisted_trunk.sh b/.ci/patch_for_twisted_trunk.sh
deleted file mode 100755
index f524581986..0000000000
--- a/.ci/patch_for_twisted_trunk.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/sh
-
-# replaces the dependency on Twisted in `python_dependencies` with trunk.
-
-set -e
-cd "$(dirname "$0")"/..
-
-sed -i -e 's#"Twisted.*"#"Twisted @ git+https://github.com/twisted/twisted"#' synapse/python_dependencies.py
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 5a98f61932..7946b76dba 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -20,19 +20,13 @@ jobs:
       - run: scripts-dev/config-lint.sh
 
   lint:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        toxenv:
-          - "check_codestyle"
-          - "check_isort"
-          - "mypy"
-
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-      - run: pip install tox
-      - run: tox -e ${{ matrix.toxenv }}
+    # This does a vanilla `poetry install` - no extras. I'm slightly anxious
+    # that we might skip some typechecks on code that uses extras. However,
+    # I think the right way to fix this is to mark any extras needed for
+    # typechecking as development dependencies. To detect this, we ought to
+    # turn up mypy's strictness: disallow unknown imports and be accept fewer
+    # uses of `Any`.
+    uses: "matrix-org/backend-meta/.github/workflows/python-poetry-ci.yml@v1"
 
   lint-crlf:
     runs-on: ubuntu-latest
@@ -71,23 +65,23 @@ jobs:
       matrix:
         python-version: ["3.7", "3.8", "3.9", "3.10"]
         database: ["sqlite"]
-        toxenv: ["py"]
+        extras: ["all"]
         include:
           # Newest Python without optional deps
           - python-version: "3.10"
-            toxenv: "py-noextras"
+            extras: ""
 
           # Oldest Python with PostgreSQL
           - python-version: "3.7"
             database: "postgres"
             postgres-version: "10"
-            toxenv: "py"
+            extras: "all"
 
           # Newest Python with newest PostgreSQL
           - python-version: "3.10"
             database: "postgres"
             postgres-version: "14"
-            toxenv: "py"
+            extras: "all"
 
     steps:
       - uses: actions/checkout@v2
@@ -99,17 +93,16 @@ jobs:
             -e POSTGRES_PASSWORD=postgres \
             -e POSTGRES_INITDB_ARGS="--lc-collate C --lc-ctype C --encoding UTF8" \
             postgres:${{ matrix.postgres-version }}
-      - uses: actions/setup-python@v2
+      - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: ${{ matrix.python-version }}
-      - run: pip install tox
+          extras: ${{ matrix.extras }}
       - name: Await PostgreSQL
         if: ${{ matrix.postgres-version }}
         timeout-minutes: 2
         run: until pg_isready -h localhost; do sleep 1; done
-      - run: tox -e ${{ matrix.toxenv }}
+      - run: poetry run trial --jobs=2 tests
         env:
-          TRIAL_FLAGS: "--jobs=2"
           SYNAPSE_POSTGRES: ${{ matrix.database == 'postgres' || '' }}
           SYNAPSE_POSTGRES_HOST: localhost
           SYNAPSE_POSTGRES_USER: postgres
@@ -156,23 +149,24 @@ jobs:
 
   trial-pypy:
     # Very slow; only run if the branch name includes 'pypy'
+    # Note: sqlite only; no postgres. Completely untested since poetry move.
     if: ${{ contains(github.ref, 'pypy') && !failure() && !cancelled() }}
     needs: linting-done
     runs-on: ubuntu-latest
     strategy:
       matrix:
         python-version: ["pypy-3.7"]
+        extras: ["all"]
 
     steps:
       - uses: actions/checkout@v2
+      # Install libs necessary for PyPy to build binary wheels for dependencies
       - run: sudo apt-get -qq install xmlsec1 libxml2-dev libxslt-dev
-      - uses: actions/setup-python@v2
+      - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: ${{ matrix.python-version }}
-      - run: pip install tox
-      - run: tox -e py
-        env:
-          TRIAL_FLAGS: "--jobs=2"
+          extras: ${{ matrix.extras }}
+      - run: poetry run trial --jobs=2 tests
       - name: Dump logs
         # Logs are most useful when the command fails, always include them.
         if: ${{ always() }}
diff --git a/.github/workflows/twisted_trunk.yml b/.github/workflows/twisted_trunk.yml
index fb9d46b7bf..8fc1affb77 100644
--- a/.github/workflows/twisted_trunk.yml
+++ b/.github/workflows/twisted_trunk.yml
@@ -6,16 +6,25 @@ on:
 
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   mypy:
     runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-      - run: .ci/patch_for_twisted_trunk.sh
-      - run: pip install tox
-      - run: tox -e mypy
+      - uses: matrix-org/setup-python-poetry@v1
+        with:
+          python-version: "3.x"
+          extras: "all"
+      - run: |
+          poetry remove twisted
+          poetry add --extras tls git+https://github.com/twisted/twisted.git#trunk
+          poetry install --no-interaction --extras "all test"
+      - run: poetry run mypy
 
   trial:
     runs-on: ubuntu-latest
@@ -23,14 +32,15 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - run: sudo apt-get -qq install xmlsec1
-      - uses: actions/setup-python@v2
+      - uses: matrix-org/setup-python-poetry@v1
         with:
-          python-version: 3.7
-      - run: .ci/patch_for_twisted_trunk.sh
-      - run: pip install tox
-      - run: tox -e py
-        env:
-          TRIAL_FLAGS: "--jobs=2"
+          python-version: "3.x"
+          extras: "all test"
+      - run: |
+          poetry remove twisted
+          poetry add --extras tls git+https://github.com/twisted/twisted.git#trunk
+          poetry install --no-interaction --extras "all test"
+      - run: poetry run trial --jobs 2 tests
 
       - name: Dump logs
         # Logs are most useful when the command fails, always include them.
@@ -55,11 +65,23 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Patch dependencies
-        run: .ci/patch_for_twisted_trunk.sh
+        # Note: The poetry commands want to create a virtualenv in /src/.venv/,
+        #       but the sytest-synapse container expects it to be in /venv/.
+        #       We symlink it before running poetry so that poetry actually
+        #       ends up installing to `/venv`.
+        run: |
+          ln -s -T /venv /src/.venv
+          poetry remove twisted
+          poetry add --extras tls git+https://github.com/twisted/twisted.git#trunk
+          poetry install --no-interaction --extras "all test"
         working-directory: /src
       - name: Run SyTest
         run: /bootstrap.sh synapse
         working-directory: /src
+        env:
+          # Use offline mode to avoid reinstalling the pinned version of
+          # twisted.
+          OFFLINE: 1
       - name: Summarise results.tap
         if: ${{ always() }}
         run: /sytest/scripts/tap_to_gha.pl /logs/results.tap
diff --git a/changelog.d/12213.bugfix b/changelog.d/12213.bugfix
new file mode 100644
index 0000000000..9278e3a9c1
--- /dev/null
+++ b/changelog.d/12213.bugfix
@@ -0,0 +1 @@
+Prevent a sync request from removing a user's busy presence status.
diff --git a/changelog.d/12319.bugfix b/changelog.d/12319.bugfix
new file mode 100644
index 0000000000..a50191feaa
--- /dev/null
+++ b/changelog.d/12319.bugfix
@@ -0,0 +1 @@
+Fix bug with incremental sync missing events when rejoining/backfilling. Contributed by Nick @ Beeper.
diff --git a/changelog.d/12340.doc b/changelog.d/12340.doc
new file mode 100644
index 0000000000..8354f2259e
--- /dev/null
+++ b/changelog.d/12340.doc
@@ -0,0 +1 @@
+Fix rendering of the documentation site when using the 'print' feature.
diff --git a/changelog.d/12344.removal b/changelog.d/12344.removal
new file mode 100644
index 0000000000..ecefa76d8e
--- /dev/null
+++ b/changelog.d/12344.removal
@@ -0,0 +1 @@
+The groups/communities feature in Synapse has been disabled by default.
diff --git a/changelog.d/12365.feature b/changelog.d/12365.feature
new file mode 100644
index 0000000000..642dea966c
--- /dev/null
+++ b/changelog.d/12365.feature
@@ -0,0 +1 @@
+Enable processing of device list updates asynchronously.
diff --git a/changelog.d/12368.doc b/changelog.d/12368.doc
new file mode 100644
index 0000000000..62e4cb2c7e
--- /dev/null
+++ b/changelog.d/12368.doc
@@ -0,0 +1 @@
+Add a manual documenting config file options.
\ No newline at end of file
diff --git a/changelog.d/12382.removal b/changelog.d/12382.removal
new file mode 100644
index 0000000000..eb91186340
--- /dev/null
+++ b/changelog.d/12382.removal
@@ -0,0 +1 @@
+Remove unstable identifiers from [MSC3440](https://github.com/matrix-org/matrix-doc/pull/3440).
diff --git a/changelog.d/12394.misc b/changelog.d/12394.misc
new file mode 100644
index 0000000000..69109fcc37
--- /dev/null
+++ b/changelog.d/12394.misc
@@ -0,0 +1 @@
+Preparation for faster-room-join work: start a background process to resynchronise the room state after a room join.
diff --git a/changelog.d/12395.misc b/changelog.d/12395.misc
new file mode 100644
index 0000000000..0a2123b294
--- /dev/null
+++ b/changelog.d/12395.misc
@@ -0,0 +1 @@
+Remove an unstable identifier from [MSC3083](https://github.com/matrix-org/matrix-doc/pull/3083).
diff --git a/changelog.d/12425.misc b/changelog.d/12425.misc
new file mode 100644
index 0000000000..3b076be0bd
--- /dev/null
+++ b/changelog.d/12425.misc
@@ -0,0 +1 @@
+Run twisted trunk CI job in the locked poetry environment.
diff --git a/changelog.d/12434.misc b/changelog.d/12434.misc
new file mode 100644
index 0000000000..88dab428d2
--- /dev/null
+++ b/changelog.d/12434.misc
@@ -0,0 +1 @@
+Run lints under poetry in CI, and remove corresponding tox lint jobs.
diff --git a/changelog.d/12438.misc b/changelog.d/12438.misc
new file mode 100644
index 0000000000..f2c07a56da
--- /dev/null
+++ b/changelog.d/12438.misc
@@ -0,0 +1 @@
+Run "main" trial tests under `poetry`.
diff --git a/changelog.d/12441.misc b/changelog.d/12441.misc
new file mode 100644
index 0000000000..c2619f1654
--- /dev/null
+++ b/changelog.d/12441.misc
@@ -0,0 +1 @@
+Bump twisted version in `poetry.lock` to work around [pip bug #9644](https://github.com/pypa/pip/issues/9644).
diff --git a/changelog.d/12445.misc b/changelog.d/12445.misc
new file mode 100644
index 0000000000..954248115a
--- /dev/null
+++ b/changelog.d/12445.misc
@@ -0,0 +1 @@
+Change Mutual Rooms' `unstable_features` flag to `uk.half-shot.msc2666.mutual_rooms` which matches the current MSC iteration.
\ No newline at end of file
diff --git a/changelog.d/12449.misc b/changelog.d/12449.misc
new file mode 100644
index 0000000000..03e08aace4
--- /dev/null
+++ b/changelog.d/12449.misc
@@ -0,0 +1 @@
+Use `poetry` to manage the virtualenv in debian packages.
diff --git a/changelog.d/12450.misc b/changelog.d/12450.misc
new file mode 100644
index 0000000000..4b1c8cba87
--- /dev/null
+++ b/changelog.d/12450.misc
@@ -0,0 +1 @@
+Fix typo in the release script help string.
diff --git a/changelog.d/12451.doc b/changelog.d/12451.doc
new file mode 100644
index 0000000000..c8b23c1285
--- /dev/null
+++ b/changelog.d/12451.doc
@@ -0,0 +1 @@
+Update documentation to reflect that both the `run_background_tasks_on` option and the options for moving stream writers off of the main process are no longer experimental.
diff --git a/changelog.d/12454.misc b/changelog.d/12454.misc
new file mode 100644
index 0000000000..cb7ff74b4c
--- /dev/null
+++ b/changelog.d/12454.misc
@@ -0,0 +1 @@
+Limit length of device_id to less than 512 characters.
diff --git a/changelog.d/12455.misc b/changelog.d/12455.misc
new file mode 100644
index 0000000000..9b19945673
--- /dev/null
+++ b/changelog.d/12455.misc
@@ -0,0 +1 @@
+Reintroduce the list of targets to the linter script, to avoid linting unwanted local-only directories during development.
diff --git a/changelog.d/12457.doc b/changelog.d/12457.doc
new file mode 100644
index 0000000000..a4871622cf
--- /dev/null
+++ b/changelog.d/12457.doc
@@ -0,0 +1 @@
+Update worker documentation and replace old `federation_reader` with `generic_worker`.
\ No newline at end of file
diff --git a/changelog.d/12464.misc b/changelog.d/12464.misc
new file mode 100644
index 0000000000..7a8cc6ba51
--- /dev/null
+++ b/changelog.d/12464.misc
@@ -0,0 +1 @@
+Dockerfile-workers: reduce the amount we install in the image.
diff --git a/changelog.d/12465.feature b/changelog.d/12465.feature
new file mode 100644
index 0000000000..642dea966c
--- /dev/null
+++ b/changelog.d/12465.feature
@@ -0,0 +1 @@
+Enable processing of device list updates asynchronously.
diff --git a/changelog.d/12466.misc b/changelog.d/12466.misc
new file mode 100644
index 0000000000..b0c2c950fe
--- /dev/null
+++ b/changelog.d/12466.misc
@@ -0,0 +1 @@
+Dockerfile-workers: give the master its own log config.
diff --git a/changelog.d/12467.misc b/changelog.d/12467.misc
new file mode 100644
index 0000000000..fbf415f707
--- /dev/null
+++ b/changelog.d/12467.misc
@@ -0,0 +1 @@
+complement-synapse-workers: factor out separate entry point script.
diff --git a/changelog.d/12474.misc b/changelog.d/12474.misc
new file mode 100644
index 0000000000..5292108b39
--- /dev/null
+++ b/changelog.d/12474.misc
@@ -0,0 +1 @@
+Back out experimental implementation of [MSC2314](https://github.com/matrix-org/matrix-spec-proposals/pull/2314).
diff --git a/changelog.d/12483.misc b/changelog.d/12483.misc
new file mode 100644
index 0000000000..88c6e3e465
--- /dev/null
+++ b/changelog.d/12483.misc
@@ -0,0 +1 @@
+Fix grammatical error in federation error response when the room version of a room is unknown.
diff --git a/debian/build_virtualenv b/debian/build_virtualenv
index e691163619..b068792592 100755
--- a/debian/build_virtualenv
+++ b/debian/build_virtualenv
@@ -30,9 +30,19 @@ case $(dpkg-architecture -q DEB_HOST_ARCH) in
         ;;
 esac
 
-# Use --builtin-venv to use the better `venv` module from CPython 3.4+ rather
-# than the 2/3 compatible `virtualenv`.
-
+# Manually install Poetry and export a pip-compatible `requirements.txt`
+# We need a Poetry pre-release as the export command is buggy in < 1.2
+TEMP_VENV="$(mktemp -d)"
+python3 -m venv "$TEMP_VENV"
+source "$TEMP_VENV/bin/activate"
+pip install -U pip
+pip install poetry==1.2.0b1
+poetry export --extras all --extras test -o exported_requirements.txt
+deactivate
+rm -rf "$TEMP_VENV"
+
+# Use --no-deps to only install pinned versions in exported_requirements.txt,
+# and to avoid https://github.com/pypa/pip/issues/9644
 dh_virtualenv \
     --install-suffix "matrix-synapse" \
     --builtin-venv \
@@ -41,9 +51,11 @@ dh_virtualenv \
     --preinstall="lxml" \
     --preinstall="mock" \
     --preinstall="wheel" \
+    --extra-pip-arg="--no-deps" \
     --extra-pip-arg="--no-cache-dir" \
     --extra-pip-arg="--compile" \
-    --extras="all,systemd,test"
+    --extras="all,systemd,test" \
+    --requirements="exported_requirements.txt"
 
 PACKAGE_BUILD_DIR="debian/matrix-synapse-py3"
 VIRTUALENV_DIR="${PACKAGE_BUILD_DIR}${DH_VIRTUALENV_INSTALL_ROOT}/matrix-synapse"
diff --git a/debian/changelog b/debian/changelog
index 71dcf9de8e..a44f7d98ff 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+matrix-synapse-py3 (1.58.0+nmu1) UNRELEASED; urgency=medium
+
+  * Non-maintainer upload.
+  * Use poetry to manage the bundled virtualenv included with this package.
+
+ -- Synapse Packaging Team <packages@matrix.org>  Wed, 30 Mar 2022 12:21:43 +0100
+
 matrix-synapse-py3 (1.57.0) stable; urgency=medium
 
   * New synapse release 1.57.0.
diff --git a/debian/clean b/debian/clean
new file mode 100644
index 0000000000..d488f298d5
--- /dev/null
+++ b/debian/clean
@@ -0,0 +1 @@
+exported_requirements.txt
diff --git a/docker/Dockerfile-workers b/docker/Dockerfile-workers
index 6fb1cdbfb0..9ccb2b22a7 100644
--- a/docker/Dockerfile-workers
+++ b/docker/Dockerfile-workers
@@ -2,10 +2,19 @@
 FROM matrixdotorg/synapse
 
 # Install deps
-RUN apt-get update
-RUN apt-get install -y supervisor redis nginx
+RUN \
+   --mount=type=cache,target=/var/cache/apt,sharing=locked \
+   --mount=type=cache,target=/var/lib/apt,sharing=locked \
+  apt-get update && \
+  DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+     redis-server nginx-light
 
-# Remove the default nginx sites
+# Install supervisord with pip instead of apt, to avoid installing a second
+# copy of python.
+RUN --mount=type=cache,target=/root/.cache/pip \
+    pip install supervisor~=4.2
+
+# Disable the default nginx sites
 RUN rm /etc/nginx/sites-enabled/default
 
 # Copy Synapse worker, nginx and supervisord configuration template files
@@ -19,5 +28,7 @@ EXPOSE 8080/tcp
 COPY ./docker/configure_workers_and_start.py /configure_workers_and_start.py
 ENTRYPOINT ["/configure_workers_and_start.py"]
 
+# Replace the healthcheck with one which checks *all* the workers. The script
+# is generated by configure_workers_and_start.py.
 HEALTHCHECK --start-period=5s --interval=15s --timeout=5s \
     CMD /bin/sh /healthcheck.sh
diff --git a/docker/complement/SynapseWorkers.Dockerfile b/docker/complement/SynapseWorkers.Dockerfile
index 982219a91e..65df2d114d 100644
--- a/docker/complement/SynapseWorkers.Dockerfile
+++ b/docker/complement/SynapseWorkers.Dockerfile
@@ -13,8 +13,8 @@ RUN curl -OL "https://github.com/caddyserver/caddy/releases/download/v2.3.0/cadd
   tar xzf caddy_2.3.0_linux_amd64.tar.gz && rm caddy_2.3.0_linux_amd64.tar.gz && mv caddy /root
 
 # Install postgresql
-RUN apt-get update
-RUN apt-get install -y postgresql
+RUN apt-get update && \
+  DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y postgresql-13
 
 # Configure a user and create a database for Synapse
 RUN pg_ctlcluster 13 main start &&  su postgres -c "echo \
@@ -34,40 +34,14 @@ WORKDIR /data
 # Copy the caddy config
 COPY conf-workers/caddy.complement.json /root/caddy.json
 
+# Copy the entrypoint
+COPY conf-workers/start-complement-synapse-workers.sh /
+
 # Expose caddy's listener ports
 EXPOSE 8008 8448
 
-ENTRYPOINT \
-  # Replace the server name in the caddy config
-  sed -i "s/{{ server_name }}/${SERVER_NAME}/g" /root/caddy.json && \
-  # Start postgres
-  pg_ctlcluster 13 main start 2>&1 && \
-  # Start caddy
-  /root/caddy start --config /root/caddy.json 2>&1 && \
-  # Set the server name of the homeserver
-  SYNAPSE_SERVER_NAME=${SERVER_NAME} \
-  # No need to report stats here
-  SYNAPSE_REPORT_STATS=no \
-  # Set postgres authentication details which will be placed in the homeserver config file
-  POSTGRES_PASSWORD=somesecret POSTGRES_USER=postgres POSTGRES_HOST=localhost \
-  # Specify the workers to test with
-  SYNAPSE_WORKER_TYPES="\
-    event_persister, \
-    event_persister, \
-    background_worker, \
-    frontend_proxy, \
-    event_creator, \
-    user_dir, \
-    media_repository, \
-    federation_inbound, \
-    federation_reader, \
-    federation_sender, \
-    synchrotron, \
-    appservice, \
-    pusher" \
-  # Run the script that writes the necessary config files and starts supervisord, which in turn
-  # starts everything else
-  /configure_workers_and_start.py
+ENTRYPOINT /start-complement-synapse-workers.sh
 
+# Update the healthcheck to have a shorter check interval
 HEALTHCHECK --start-period=5s --interval=1s --timeout=1s \
     CMD /bin/sh /healthcheck.sh
diff --git a/docker/complement/conf-workers/start-complement-synapse-workers.sh b/docker/complement/conf-workers/start-complement-synapse-workers.sh
new file mode 100755
index 0000000000..2c1e05bd62
--- /dev/null
+++ b/docker/complement/conf-workers/start-complement-synapse-workers.sh
@@ -0,0 +1,50 @@
+#!/bin/bash
+#
+# Default ENTRYPOINT for the docker image used for testing synapse with workers under complement
+
+set -e
+
+function log {
+    d=$(date +"%Y-%m-%d %H:%M:%S,%3N")
+    echo "$d $@"
+}
+
+# Replace the server name in the caddy config
+sed -i "s/{{ server_name }}/${SERVER_NAME}/g" /root/caddy.json
+
+log "starting postgres"
+pg_ctlcluster 13 main start
+
+log "starting caddy"
+/root/caddy start --config /root/caddy.json
+
+# Set the server name of the homeserver
+export SYNAPSE_SERVER_NAME=${SERVER_NAME}
+
+# No need to report stats here
+export SYNAPSE_REPORT_STATS=no
+
+# Set postgres authentication details which will be placed in the homeserver config file
+export POSTGRES_PASSWORD=somesecret
+export POSTGRES_USER=postgres
+export POSTGRES_HOST=localhost
+
+# Specify the workers to test with
+export SYNAPSE_WORKER_TYPES="\
+    event_persister, \
+    event_persister, \
+    background_worker, \
+    frontend_proxy, \
+    event_creator, \
+    user_dir, \
+    media_repository, \
+    federation_inbound, \
+    federation_reader, \
+    federation_sender, \
+    synchrotron, \
+    appservice, \
+    pusher"
+
+# Run the script that writes the necessary config files and starts supervisord, which in turn
+# starts everything else
+exec /configure_workers_and_start.py
diff --git a/docker/conf-workers/supervisord.conf.j2 b/docker/conf-workers/supervisord.conf.j2
index 0de2c6143b..408ef72787 100644
--- a/docker/conf-workers/supervisord.conf.j2
+++ b/docker/conf-workers/supervisord.conf.j2
@@ -5,6 +5,9 @@
 nodaemon=true
 user=root
 
+[include]
+files = /etc/supervisor/conf.d/*.conf
+
 [program:nginx]
 command=/usr/sbin/nginx -g "daemon off;"
 priority=500
diff --git a/docker/configure_workers_and_start.py b/docker/configure_workers_and_start.py
index 3e91024e8c..23cac18e8d 100755
--- a/docker/configure_workers_and_start.py
+++ b/docker/configure_workers_and_start.py
@@ -29,7 +29,7 @@
 import os
 import subprocess
 import sys
-from typing import Any, Dict, Set
+from typing import Any, Dict, Mapping, Set
 
 import jinja2
 import yaml
@@ -341,7 +341,7 @@ def generate_worker_files(environ, config_path: str, data_dir: str):
     # base shared worker jinja2 template.
     #
     # This config file will be passed to all workers, included Synapse's main process.
-    shared_config = {"listeners": listeners}
+    shared_config: Dict[str, Any] = {"listeners": listeners}
 
     # The supervisord config. The contents of which will be inserted into the
     # base supervisord jinja2 template.
@@ -446,21 +446,7 @@ def generate_worker_files(environ, config_path: str, data_dir: str):
 
         # Write out the worker's logging config file
 
-        # Check whether we should write worker logs to disk, in addition to the console
-        extra_log_template_args = {}
-        if environ.get("SYNAPSE_WORKERS_WRITE_LOGS_TO_DISK"):
-            extra_log_template_args["LOG_FILE_PATH"] = "{dir}/logs/{name}.log".format(
-                dir=data_dir, name=worker_name
-            )
-
-        # Render and write the file
-        log_config_filepath = "/conf/workers/{name}.log.config".format(name=worker_name)
-        convert(
-            "/conf/log.config",
-            log_config_filepath,
-            worker_name=worker_name,
-            **extra_log_template_args,
-        )
+        log_config_filepath = generate_worker_log_config(environ, worker_name, data_dir)
 
         # Then a worker config file
         convert(
@@ -496,6 +482,10 @@ def generate_worker_files(environ, config_path: str, data_dir: str):
 
     # Finally, we'll write out the config files.
 
+    # log config for the master process
+    master_log_config = generate_worker_log_config(environ, "master", data_dir)
+    shared_config["log_config"] = master_log_config
+
     # Shared homeserver config
     convert(
         "/conf/shared.yaml.j2",
@@ -512,9 +502,10 @@ def generate_worker_files(environ, config_path: str, data_dir: str):
     )
 
     # Supervisord config
+    os.makedirs("/etc/supervisor", exist_ok=True)
     convert(
         "/conf/supervisord.conf.j2",
-        "/etc/supervisor/conf.d/supervisord.conf",
+        "/etc/supervisor/supervisord.conf",
         main_config_path=config_path,
         worker_config=supervisord_config,
     )
@@ -532,12 +523,28 @@ def generate_worker_files(environ, config_path: str, data_dir: str):
         os.mkdir(log_dir)
 
 
-def start_supervisord():
-    """Starts up supervisord which then starts and monitors all other necessary processes
+def generate_worker_log_config(
+    environ: Mapping[str, str], worker_name: str, data_dir: str
+) -> str:
+    """Generate a log.config file for the given worker.
 
-    Raises: CalledProcessError if calling start.py return a non-zero exit code.
+    Returns: the path to the generated file
     """
-    subprocess.run(["/usr/bin/supervisord"], stdin=subprocess.PIPE)
+    # Check whether we should write worker logs to disk, in addition to the console
+    extra_log_template_args = {}
+    if environ.get("SYNAPSE_WORKERS_WRITE_LOGS_TO_DISK"):
+        extra_log_template_args["LOG_FILE_PATH"] = "{dir}/logs/{name}.log".format(
+            dir=data_dir, name=worker_name
+        )
+    # Render and write the file
+    log_config_filepath = "/conf/workers/{name}.log.config".format(name=worker_name)
+    convert(
+        "/conf/log.config",
+        log_config_filepath,
+        worker_name=worker_name,
+        **extra_log_template_args,
+    )
+    return log_config_filepath
 
 
 def main(args, environ):
@@ -567,7 +574,13 @@ def main(args, environ):
 
     # Start supervisord, which will start Synapse, all of the configured worker
     # processes, redis, nginx etc. according to the config we created above.
-    start_supervisord()
+    log("Starting supervisord")
+    os.execl(
+        "/usr/local/bin/supervisord",
+        "supervisord",
+        "-c",
+        "/etc/supervisor/supervisord.conf",
+    )
 
 
 if __name__ == "__main__":
diff --git a/docs/SUMMARY.md b/docs/SUMMARY.md
index 6aa48e1919..65570cefbe 100644
--- a/docs/SUMMARY.md
+++ b/docs/SUMMARY.md
@@ -17,6 +17,7 @@
 # Usage
   - [Federation](federate.md)
   - [Configuration](usage/configuration/README.md)
+    - [Configuration Manual](usage/configuration/config_documentation.md) 
     - [Homeserver Sample Config File](usage/configuration/homeserver_sample_config.md)
     - [Logging Sample Config File](usage/configuration/logging_sample_config.md)
     - [Structured Logging](structured_logging.md)
diff --git a/docs/code_style.md b/docs/code_style.md
index ebda6dcc85..db7edcd76b 100644
--- a/docs/code_style.md
+++ b/docs/code_style.md
@@ -6,60 +6,36 @@ The Synapse codebase uses a number of code formatting tools in order to
 quickly and automatically check for formatting (and sometimes logical)
 errors in code.
 
-The necessary tools are detailed below.
+The necessary tools are:
 
-First install them with:
+- [black](https://black.readthedocs.io/en/stable/), a source code formatter;
+- [isort](https://pycqa.github.io/isort/), which organises each file's imports;
+- [flake8](https://flake8.pycqa.org/en/latest/), which can spot common errors; and
+- [mypy](https://mypy.readthedocs.io/en/stable/), a type checker.
+
+Install them with:
 
 ```sh
 pip install -e ".[lint,mypy]"
 ```
 
--   **black**
-
-    The Synapse codebase uses [black](https://pypi.org/project/black/)
-    as an opinionated code formatter, ensuring all comitted code is
-    properly formatted.
-
-    Have `black` auto-format your code (it shouldn't change any
-    functionality) with:
-
-    ```sh
-    black .
-    ```
-
--   **flake8**
-
-    `flake8` is a code checking tool. We require code to pass `flake8`
-    before being merged into the codebase.
-
-    Check all application and test code with:
+The easiest way to run the lints is to invoke the linter script as follows.
 
-    ```sh
-    flake8 .
-    ```
-
--   **isort**
-
-    `isort` ensures imports are nicely formatted, and can suggest and
-    auto-fix issues such as double-importing.
-
-    Auto-fix imports with:
-
-    ```sh
-    isort .
-    ```
+```sh
+scripts-dev/lint.sh
+```
 
 It's worth noting that modern IDEs and text editors can run these tools
 automatically on save. It may be worth looking into whether this
 functionality is supported in your editor for a more convenient
-development workflow. It is not, however, recommended to run `flake8` on
-save as it takes a while and is very resource intensive.
+development workflow. It is not, however, recommended to run `flake8` or `mypy`
+on save as they take a while and can be very resource intensive.
 
 ## General rules
 
 -   **Naming**:
-    -   Use camel case for class and type names
-    -   Use underscores for functions and variables.
+    -   Use `CamelCase` for class and type names
+    -   Use underscores for `function_names` and `variable_names`.
 -   **Docstrings**: should follow the [google code
     style](https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings).
     See the
diff --git a/docs/systemd-with-workers/README.md b/docs/systemd-with-workers/README.md
index b160d93528..d516501085 100644
--- a/docs/systemd-with-workers/README.md
+++ b/docs/systemd-with-workers/README.md
@@ -10,15 +10,15 @@ See the folder [system](https://github.com/matrix-org/synapse/tree/develop/docs/
 for the systemd unit files.
 
 The folder [workers](https://github.com/matrix-org/synapse/tree/develop/docs/systemd-with-workers/workers/)
-contains an example configuration for the `federation_reader` worker.
+contains an example configuration for the `generic_worker` worker.
 
 ## Synapse configuration files
 
 See [the worker documentation](../workers.md) for information on how to set up the
 configuration files and reverse-proxy correctly.
-Below is a sample `federation_reader` worker configuration file.
+Below is a sample `generic_worker` worker configuration file.
 ```yaml
-{{#include workers/federation_reader.yaml}}
+{{#include workers/generic_worker.yaml}}
 ```
 
 Systemd manages daemonization itself, so ensure that none of the configuration
@@ -61,9 +61,9 @@ systemctl stop matrix-synapse.target
 # Restart the master alone
 systemctl start matrix-synapse.service
 
-# Restart a specific worker (eg. federation_reader); the master is
+# Restart a specific worker (eg. generic_worker); the master is
 # unaffected by this.
-systemctl restart matrix-synapse-worker@federation_reader.service
+systemctl restart matrix-synapse-worker@generic_worker.service
 
 # Add a new worker (assuming all configs are set up already)
 systemctl enable matrix-synapse-worker@federation_writer.service
diff --git a/docs/systemd-with-workers/workers/federation_reader.yaml b/docs/systemd-with-workers/workers/federation_reader.yaml
deleted file mode 100644
index 13e69e62c9..0000000000
--- a/docs/systemd-with-workers/workers/federation_reader.yaml
+++ /dev/null
@@ -1,13 +0,0 @@
-worker_app: synapse.app.federation_reader
-worker_name: federation_reader1
-
-worker_replication_host: 127.0.0.1
-worker_replication_http_port: 9093
-
-worker_listeners:
-    - type: http
-      port: 8011
-      resources:
-          - names: [federation]
-
-worker_log_config: /etc/matrix-synapse/federation-reader-log.yaml
diff --git a/docs/systemd-with-workers/workers/generic_worker.yaml b/docs/systemd-with-workers/workers/generic_worker.yaml
new file mode 100644
index 0000000000..8561e2cda5
--- /dev/null
+++ b/docs/systemd-with-workers/workers/generic_worker.yaml
@@ -0,0 +1,13 @@
+worker_app: synapse.app.generic_worker
+worker_name: generic_worker1
+
+worker_replication_host: 127.0.0.1
+worker_replication_http_port: 9093
+
+worker_listeners:
+  - type: http
+    port: 8011
+    resources:
+      - names: [client, federation]
+
+worker_log_config: /etc/matrix-synapse/generic-worker-log.yaml
diff --git a/docs/upgrade.md b/docs/upgrade.md
index 023872490e..a0c797ea9f 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -85,6 +85,13 @@ process, for example:
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
 
+# Upgrading to v1.58.0
+
+## Groups/communities feature has been disabled by default
+
+The non-standard groups/communities feature in Synapse has been disabled by default
+and will be removed in Synapse v1.61.0.
+
 # Upgrading to v1.57.0
 
 ## Changes to database schema for application services
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
new file mode 100644
index 0000000000..9c864af6ec
--- /dev/null
+++ b/docs/usage/configuration/config_documentation.md
@@ -0,0 +1,3412 @@
+# Configuring Synapse
+
+This is intended as a guide to the Synapse configuration. The behavior of a Synapse instance can be modified 
+through the many configuration settings documented here — each config option is explained, 
+including what the default is, how to change the default and what sort of behaviour the setting governs.
+Also included is an example configuration for each setting. If you don't want to spend a lot of time 
+thinking about options, the config as generated sets sensible defaults for all values. Do note however that the
+database defaults to SQLite, which is not recommended for production usage. You can read more on this subject 
+[here](../../setup/installation.md#using-postgresql).
+
+## Config Conventions
+
+Configuration options that take a time period can be set using a number
+followed by a letter. Letters have the following meanings:
+
+* `s` = second
+* `m` = minute
+* `h` = hour
+* `d` = day
+* `w` = week
+* `y` = year
+
+For example, setting `redaction_retention_period: 5m` would remove redacted
+messages from the database after 5 minutes, rather than 5 months.
+
+### YAML 
+The configuration file is a [YAML](https://yaml.org/) file, which means that certain syntax rules
+apply if you want your config file to be read properly. A few helpful things to know:
+* `#` before any option in the config will comment out that setting and either a default (if available) will 
+   be applied or Synapse will ignore the setting. Thus, in example #1 below, the setting will be read and
+   applied, but in example #2 the setting will not be read and a default will be applied.  
+
+   Example #1:
+   ```yaml
+   pid_file: DATADIR/homeserver.pid
+   ```
+   Example #2:
+   ```yaml
+   #pid_file: DATADIR/homeserver.pid
+   ```
+* Indentation matters! The indentation before a setting
+  will determine whether a given setting is read as part of another
+  setting, or considered on its own. Thus, in example #1, the `enabled` setting
+  is read as a sub-option of the `presence` setting, and will be properly applied.
+  
+  However, the lack of indentation before the `enabled` setting in example #2 means
+  that when reading the config, Synapse will consider both `presence` and `enabled` as
+  different settings. In this case, `presence` has no value, and thus a default applied, and `enabled`
+  is an option that Synapse doesn't recognize and thus ignores.
+  
+  Example #1: 
+  ```yaml
+  presence:
+    enabled: false
+  ```
+  Example #2:
+  ```yaml
+  presence:
+  enabled: false
+  ```
+  In this manual, all top-level settings (ones with no indentation) are identified 
+  at the beginning of their section (i.e. "Config option: `example_setting`") and 
+  the sub-options, if any, are identified and listed in the body of the section. 
+  In addition, each setting has an example of its usage, with the proper indentation
+  shown. 
+
+  
+## Modules
+
+Server admins can expand Synapse's functionality with external modules.
+
+See [here](../../modules/index.md) for more
+documentation on how to configure or create custom modules for Synapse.
+
+
+---
+Config option: `modules`
+
+Use the `module` sub-option to add modules under this option to extend functionality. 
+The `module` setting then has a sub-option, `config`, which can be used to define some configuration
+for the `module`.
+
+Defaults to none.
+
+Example configuration:
+```yaml
+modules:
+  - module: my_super_module.MySuperClass
+    config:
+      do_thing: true
+  - module: my_other_super_module.SomeClass
+    config: {}
+```
+---
+## Server ##
+
+Define your homeserver name and other base options.
+
+---
+Config option: `server_name`
+
+This sets the public-facing domain of the server.
+
+The `server_name` name will appear at the end of usernames and room addresses
+created on your server. For example if the `server_name` was example.com,
+usernames on your server would be in the format `@user:example.com`
+
+In most cases you should avoid using a matrix specific subdomain such as
+matrix.example.com or synapse.example.com as the `server_name` for the same
+reasons you wouldn't use user@email.example.com as your email address.
+See [here](../../delegate.md)
+for information on how to host Synapse on a subdomain while preserving
+a clean `server_name`.
+
+The `server_name` cannot be changed later so it is important to
+configure this correctly before you start Synapse. It should be all
+lowercase and may contain an explicit port.
+
+There is no default for this option. 
+ 
+Example configuration #1:
+```yaml
+server_name: matrix.org 
+```
+Example configuration #2:
+```yaml
+server_name: localhost:8080
+```
+---
+Config option: `pid_file`
+
+When running Synapse as a daemon, the file to store the pid in. Defaults to none.
+
+Example configuration:
+```yaml
+pid_file: DATADIR/homeserver.pid
+```
+---
+Config option: `web_client_location`
+
+The absolute URL to the web client which `/` will redirect to. Defaults to none. 
+
+Example configuration:
+```yaml
+web_client_location: https://riot.example.com/
+```
+---
+Config option: `public_baseurl`
+
+The public-facing base URL that clients use to access this Homeserver (not
+including _matrix/...). This is the same URL a user might enter into the
+'Custom Homeserver URL' field on their client. If you use Synapse with a
+reverse proxy, this should be the URL to reach Synapse via the proxy.
+Otherwise, it should be the URL to reach Synapse's client HTTP listener (see
+'listeners' below).
+
+Defaults to `https://<server_name>/`.
+
+Example configuration:
+```yaml
+public_baseurl: https://example.com/
+```
+---
+Config option: `serve_server_wellknown`
+
+By default, other servers will try to reach our server on port 8448, which can
+be inconvenient in some environments.
+
+Provided `https://<server_name>/` on port 443 is routed to Synapse, this
+option configures Synapse to serve a file at `https://<server_name>/.well-known/matrix/server`. 
+This will tell other servers to send traffic to port 443 instead.
+
+This option currently defaults to false.
+
+See https://matrix-org.github.io/synapse/latest/delegate.html for more
+information.
+
+Example configuration:
+```yaml
+serve_server_wellknown: true
+```
+---
+Config option: `soft_file_limit`
+ 
+Set the soft limit on the number of file descriptors synapse can use.
+Zero is used to indicate synapse should set the soft limit to the hard limit.
+Defaults to 0. 
+
+Example configuration:
+```yaml
+soft_file_limit: 3
+```
+---
+Config option: `presence`
+
+Presence tracking allows users to see the state (e.g online/offline)
+of other local and remote users. Set the `enabled` sub-option to false to  
+disable presence tracking on this homeserver. Defaults to true. 
+This option replaces the previous top-level 'use_presence' option.
+
+Example configuration:
+```yaml
+presence:
+  enabled: false
+```
+---
+Config option: `require_auth_for_profile_requests`
+
+Whether to require authentication to retrieve profile data (avatars, display names) of other 
+users through the client API. Defaults to false. Note that profile data is also available 
+via the federation API, unless `allow_profile_lookup_over_federation` is set to false.
+
+Example configuration:
+```yaml
+require_auth_for_profile_requests: true
+```
+---
+Config option: `limit_profile_requests_to_users_who_share_rooms`
+
+Use this option to require a user to share a room with another user in order
+to retrieve their profile information. Only checked on Client-Server 
+requests. Profile requests from other servers should be checked by the
+requesting server. Defaults to false.
+
+Example configuration: 
+```yaml
+limit_profile_requests_to_users_who_share_rooms: true
+```
+---
+Config option: `include_profile_data_on_invite`
+
+Use this option to prevent a user's profile data from being retrieved and
+displayed in a room until they have joined it. By default, a user's
+profile data is included in an invite event, regardless of the values
+of the above two settings, and whether or not the users share a server.
+Defaults to true.
+
+Example configuration:
+```yaml
+include_profile_data_on_invite: false
+```
+---
+Config option: `allow_public_rooms_without_auth`
+
+If set to true, removes the need for authentication to access the server's
+public rooms directory through the client API, meaning that anyone can
+query the room directory. Defaults to false.
+
+Example configuration:
+```yaml
+allow_public_rooms_without_auth: true
+```
+---
+Config option: `allow_public_rooms_without_auth`
+
+If set to true, allows any other homeserver to fetch the server's public
+rooms directory via federation. Defaults to false.
+
+Example configuration:
+```yaml
+allow_public_rooms_over_federation: true
+```
+---
+Config option: `default_room_version`
+
+The default room version for newly created rooms on this server.
+
+Known room versions are listed [here](https://spec.matrix.org/latest/rooms/#complete-list-of-room-versions)
+
+For example, for room version 1, `default_room_version` should be set
+to "1". 
+
+Currently defaults to "9".
+
+Example configuration:
+```yaml
+default_room_version: "8"
+```
+---
+Config option: `gc_thresholds`
+
+The garbage collection threshold parameters to pass to `gc.set_threshold`, if defined.
+Defaults to none. 
+
+Example configuration:
+```yaml
+gc_thresholds: [700, 10, 10]
+```
+---
+Config option: `gc_min_interval`
+
+The minimum time in seconds between each GC for a generation, regardless of
+the GC thresholds. This ensures that we don't do GC too frequently. A value of `[1s, 10s, 30s]` 
+indicates that a second must pass between consecutive generation 0 GCs, etc.
+
+Defaults to `[1s, 10s, 30s]`.
+
+Example configuration:
+```yaml
+gc_min_interval: [0.5s, 30s, 1m]
+```
+---
+Config option: `filter_timeline_limit`
+
+Set the limit on the returned events in the timeline in the get
+and sync operations. Defaults to 100. A value of -1 means no upper limit.
+
+
+Example configuration:
+```yaml
+filter_timeline_limit: 5000
+```
+---
+Config option: `block_non_admin_invites`
+
+Whether room invites to users on this server should be blocked
+(except those sent by local server admins). Defaults to false.
+
+Example configuration:
+```yaml
+block_non_admin_invites: true
+```
+---
+Config option: `enable_search`
+
+If set to false, new messages will not be indexed for searching and users
+will receive errors when searching for messages. Defaults to true.
+
+Example configuration:
+```yaml
+enable_search: false
+```
+---
+Config option: `ip_range_blacklist`
+ 
+This option prevents outgoing requests from being sent to the specified blacklisted IP address
+CIDR ranges. If this option is not specified then it defaults to private IP
+address ranges (see the example below).
+
+The blacklist applies to the outbound requests for federation, identity servers,
+push servers, and for checking key validity for third-party invite events.
+
+(0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
+listed here, since they correspond to unroutable addresses.)
+
+This option replaces `federation_ip_range_blacklist` in Synapse v1.25.0.
+
+Note: The value is ignored when an HTTP proxy is in use.
+
+Example configuration:
+```yaml
+ip_range_blacklist:
+  - '127.0.0.0/8'
+  - '10.0.0.0/8'
+  - '172.16.0.0/12'
+  - '192.168.0.0/16'
+  - '100.64.0.0/10'
+  - '192.0.0.0/24'
+  - '169.254.0.0/16'
+  - '192.88.99.0/24'
+  - '198.18.0.0/15'
+  - '192.0.2.0/24'
+  - '198.51.100.0/24'
+  - '203.0.113.0/24'
+  - '224.0.0.0/4'
+  - '::1/128'
+  - 'fe80::/10'
+  - 'fc00::/7'
+  - '2001:db8::/32'
+  - 'ff00::/8'
+  - 'fec0::/10'
+```
+---
+Config option: `ip_range_whitelist`
+
+List of IP address CIDR ranges that should be allowed for federation,
+identity servers, push servers, and for checking key validity for
+third-party invite events. This is useful for specifying exceptions to
+wide-ranging blacklisted target IP ranges - e.g. for communication with
+a push server only visible in your network.
+
+This whitelist overrides `ip_range_blacklist` and defaults to an empty
+list.
+
+Example configuration:
+```yaml
+ip_range_whitelist:
+   - '192.168.1.1'
+```
+---
+Config option: `listeners`
+
+List of ports that Synapse should listen on, their purpose and their
+configuration.
+
+Sub-options for each listener include:
+
+* `port`: the TCP port to bind to. 
+
+* `bind_addresses`: a list of local addresses to listen on. The default is
+       'all local interfaces'.
+
+* `type`: the type of listener. Normally `http`, but other valid options are:
+    
+   * `manhole`: (see the docs [here](../../manhole.md)),
+
+   * `metrics`: (see the docs [here](../../metrics-howto.md)),
+
+   * `replication`: (see the docs [here](../../workers.md)).
+
+* `tls`: set to true to enable TLS for this listener. Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.
+
+* `x_forwarded`: Only valid for an 'http' listener. Set to true to use the X-Forwarded-For header as the client IP. Useful when Synapse is
+   behind a reverse-proxy.
+
+* `resources`: Only valid for an 'http' listener. A list of resources to host
+   on this port. Sub-options for each resource are:
+
+   * `names`: a list of names of HTTP resources. See below for a list of valid resource names.
+
+   * `compress`: set to true to enable HTTP compression for this resource.
+
+* `additional_resources`: Only valid for an 'http' listener. A map of
+   additional endpoints which should be loaded via dynamic modules.
+
+Valid resource names are:
+
+* `client`: the client-server API (/_matrix/client), and the synapse admin API (/_synapse/admin). Also implies 'media' and 'static'.
+
+* `consent`: user consent forms (/_matrix/consent). See [here](../../consent_tracking.md) for more.
+
+* `federation`: the server-server API (/_matrix/federation). Also implies `media`, `keys`, `openid`
+
+* `keys`: the key discovery API (/_matrix/keys).
+
+* `media`: the media API (/_matrix/media).
+
+* `metrics`: the metrics interface. See [here](../../metrics-howto.md).
+
+* `openid`: OpenID authentication. See [here](../../openid.md).
+
+* `replication`: the HTTP replication API (/_synapse/replication). See [here](../../workers.md).
+
+* `static`: static resources under synapse/static (/_matrix/static). (Mostly useful for 'fallback authentication'.)
+
+Example configuration #1:
+```yaml
+listeners:
+  # TLS-enabled listener: for when matrix traffic is sent directly to synapse.
+  #
+  # (Note that you will also need to give Synapse a TLS key and certificate: see the TLS section
+  # below.)
+  #
+  - port: 8448
+    type: http
+    tls: true
+    resources:
+      - names: [client, federation]
+```
+Example configuration #2:
+```yaml
+listeners:
+  # Unsecure HTTP listener: for when matrix traffic passes through a reverse proxy
+  # that unwraps TLS.
+  #
+  # If you plan to use a reverse proxy, please see
+  # https://matrix-org.github.io/synapse/latest/reverse_proxy.html.
+  #
+  - port: 8008
+    tls: false
+    type: http
+    x_forwarded: true
+    bind_addresses: ['::1', '127.0.0.1']
+
+    resources:
+      - names: [client, federation]
+        compress: false
+
+    # example additional_resources:
+    additional_resources:
+      "/_matrix/my/custom/endpoint":
+        module: my_module.CustomRequestHandler
+        config: {}
+
+  # Turn on the twisted ssh manhole service on localhost on the given
+  # port.
+  - port: 9000
+    bind_addresses: ['::1', '127.0.0.1']
+    type: manhole
+```
+---
+Config option: `manhole_settings`
+
+Connection settings for the manhole. You can find more information
+on the manhole [here](../../manhole.md). Manhole sub-options include:
+* `username` : the username for the manhole. This defaults to 'matrix'.
+* `password`: The password for the manhole. This defaults to 'rabbithole'.
+* `ssh_priv_key_path` and `ssh_pub_key_path`: The private and public SSH key pair used to encrypt the manhole traffic.
+  If these are left unset, then hardcoded and non-secret keys are used,
+  which could allow traffic to be intercepted if sent over a public network.
+
+Example configuration:
+```yaml
+manhole_settings:
+  username: manhole
+  password: mypassword
+  ssh_priv_key_path: CONFDIR/id_rsa
+  ssh_pub_key_path: CONFDIR/id_rsa.pub
+```
+---
+Config option: `dummy_events_threshold`
+
+Forward extremities can build up in a room due to networking delays between
+homeservers. Once this happens in a large room, calculation of the state of
+that room can become quite expensive. To mitigate this, once the number of
+forward extremities reaches a given threshold, Synapse will send an
+`org.matrix.dummy_event` event, which will reduce the forward extremities
+in the room.
+
+This setting defines the threshold (i.e. number of forward extremities in the room) at which dummy events are sent. 
+The default value is 10.
+
+Example configuration:
+```yaml
+dummy_events_threshold: 5
+```
+---
+## Homeserver blocking ##
+Useful options for Synapse admins.
+
+---
+
+Config option: `admin_contact`
+
+How to reach the server admin, used in `ResourceLimitError`. Defaults to none. 
+
+Example configuration:
+```yaml
+admin_contact: 'mailto:admin@server.com'
+```
+---
+Config option: `hs_disabled` and `hs_disabled_message`
+
+Blocks users from connecting to the homeserver and provides a human-readable reason
+why the connection was blocked. Defaults to false. 
+
+Example configuration:
+```yaml
+hs_disabled: true
+hs_disabled_message: 'Reason for why the HS is blocked'
+```
+---
+Config option: `limit_usage_by_mau`
+
+This option disables/enables monthly active user blocking. Used in cases where the admin or 
+server owner wants to limit to the number of monthly active users. When enabled and a limit is 
+reached the server returns a `ResourceLimitError` with error type `Codes.RESOURCE_LIMIT_EXCEEDED`.
+Defaults to false. If this is enabled, a value for `max_mau_value` must also be set.
+
+Example configuration:
+```yaml
+limit_usage_by_mau: true 
+```
+---
+Config option: `max_mau_value`
+
+This option sets the hard limit of monthly active users above which the server will start 
+blocking user actions if `limit_usage_by_mau` is enabled. Defaults to 0.  
+
+Example configuration:
+```yaml
+max_mau_value: 50
+```
+---
+Config option: `mau_trial_days`
+
+The option `mau_trial_days` is a means to add a grace period for active users. It
+means that users must be active for the specified number of days before they
+can be considered active and guards against the case where lots of users
+sign up in a short space of time never to return after their initial
+session. Defaults to 0. 
+
+Example configuration:
+```yaml
+mau_trial_days: 5
+```
+---
+Config option: `mau_limit_alerting`
+
+The option `mau_limit_alerting` is a means of limiting client-side alerting
+should the mau limit be reached. This is useful for small instances
+where the admin has 5 mau seats (say) for 5 specific people and no
+interest increasing the mau limit further. Defaults to true, which
+means that alerting is enabled.
+
+Example configuration:
+```yaml
+mau_limit_alerting: false
+```
+---
+Config option: `mau_stats_only`
+
+If enabled, the metrics for the number of monthly active users will
+be populated, however no one will be limited based on these numbers. If `limit_usage_by_mau`
+is true, this is implied to be true. Defaults to false. 
+
+Example configuration:
+```yaml
+mau_stats_only: true
+```
+---
+Config option: `mau_limit_reserved_threepids`
+
+Sometimes the server admin will want to ensure certain accounts are
+never blocked by mau checking. These accounts are specified by this option.
+Defaults to none. Add accounts by specifying the `medium` and `address` of the
+reserved threepid (3rd party identifier).
+
+Example configuration:
+```yaml
+mau_limit_reserved_threepids:
+  - medium: 'email'
+    address: 'reserved_user@example.com'
+```
+---
+Config option: `server_context`
+
+This option is used by phonehome stats to group together related servers.
+Defaults to none. 
+
+Example configuration:
+```yaml
+server_context: context
+```
+---
+Config option: `limit_remote_rooms`
+
+When this option is enabled, the room "complexity" will be checked before a user
+joins a new remote room. If it is above the complexity limit, the server will
+disallow joining, or will instantly leave. This is useful for homeservers that are
+resource-constrained. Options for this setting include:
+* `enabled`: whether this check is enabled. Defaults to false.
+* `complexity`: the limit above which rooms cannot be joined. The default is 1.0.
+* `complexity_error`: override the error which is returned when the room is too complex with a
+   custom message. 
+* `admins_can_join`: allow server admins to join complex rooms. Default is false.
+
+Room complexity is an arbitrary measure based on factors such as the number of
+users in the room. 
+
+Example configuration:
+```yaml
+limit_remote_rooms:
+  enabled: true
+  complexity: 0.5
+  complexity_error: "I can't let you do that, Dave."
+  admins_can_join: true
+```
+---
+Config option: `require_membership_for_aliases`
+
+Whether to require a user to be in the room to add an alias to it.
+Defaults to true.
+
+Example configuration:
+```yaml
+require_membership_for_aliases: false
+```
+---
+Config option: `allow_per_room_profiles`
+
+Whether to allow per-room membership profiles through the sending of membership
+events with profile information that differs from the target's global profile.
+Defaults to true.
+
+Example configuration:
+```yaml
+allow_per_room_profiles: false
+```
+---
+Config option: `max_avatar_size`
+
+The largest permissible file size in bytes for a user avatar. Defaults to no restriction.
+Use M for MB and K for KB. 
+
+Note that user avatar changes will not work if this is set without using Synapse's media repository.
+
+Example configuration:
+```yaml
+max_avatar_size: 10M
+```
+---
+Config option: `allowed_avatar_mimetypes`
+
+The MIME types allowed for user avatars. Defaults to no restriction.
+
+Note that user avatar changes will not work if this is set without
+using Synapse's media repository.
+
+Example configuration:
+```yaml
+allowed_avatar_mimetypes: ["image/png", "image/jpeg", "image/gif"]
+```
+---
+Config option: `redaction_retention_period`
+
+How long to keep redacted events in unredacted form in the database. After
+this period redacted events get replaced with their redacted form in the DB.
+
+Defaults to `7d`. Set to `null` to disable.
+
+Example configuration:
+```yaml
+redaction_retention_period: 28d
+```
+---
+Config option: `user_ips_max_age` 
+
+How long to track users' last seen time and IPs in the database.
+
+Defaults to `28d`. Set to `null` to disable clearing out of old rows.
+
+Example configuration:
+```yaml
+user_ips_max_age: 14d
+```
+---
+Config option: `request_token_inhibit_3pid_errors`
+
+Inhibits the `/requestToken` endpoints from returning an error that might leak
+information about whether an e-mail address is in use or not on this
+homeserver. Defaults to false. 
+Note that for some endpoints the error situation is the e-mail already being
+used, and for others the error is entering the e-mail being unused.
+If this option is enabled, instead of returning an error, these endpoints will
+act as if no error happened and return a fake session ID ('sid') to clients.
+
+Example configuration:
+```yaml
+request_token_inhibit_3pid_errors: true
+```
+---
+Config option: `next_link_domain_whitelist`
+
+A list of domains that the domain portion of `next_link` parameters
+must match.
+
+This parameter is optionally provided by clients while requesting
+validation of an email or phone number, and maps to a link that
+users will be automatically redirected to after validation
+succeeds. Clients can make use this parameter to aid the validation
+process.
+
+The whitelist is applied whether the homeserver or an identity server is handling validation.
+
+The default value is no whitelist functionality; all domains are
+allowed. Setting this value to an empty list will instead disallow
+all domains.
+
+Example configuration:
+```yaml
+next_link_domain_whitelist: ["matrix.org"]
+```
+---
+Config option: `templates` and `custom_template_directory`
+
+These options define templates to use when generating email or HTML page contents.
+The `custom_template_directory` determines which directory Synapse will try to 
+find template files in to use to generate email or HTML page contents.
+If not set, or a file is not found within the template directory, a default 
+template from within the Synapse package will be used.
+
+See [here](../../templates.md) for more
+information about using custom templates.
+
+Example configuration:
+```yaml
+templates:
+  custom_template_directory: /path/to/custom/templates/
+```
+---
+Config option: `retention`
+
+This option and the associated options determine message retention policy at the
+server level.
+
+Room admins and mods can define a retention period for their rooms using the
+`m.room.retention` state event, and server admins can cap this period by setting
+the `allowed_lifetime_min` and `allowed_lifetime_max` config options.
+
+If this feature is enabled, Synapse will regularly look for and purge events
+which are older than the room's maximum retention period. Synapse will also
+filter events received over federation so that events that should have been 
+purged are ignored and not stored again. 
+
+The message retention policies feature is disabled by default.
+
+This setting has the following sub-options:
+* `default_policy`: Default retention policy. If set, Synapse will apply it to rooms that lack the
+   'm.room.retention' state event. This option is further specified by the 
+   `min_lifetime` and `max_lifetime` sub-options associated with it. Note that the 
+    value of `min_lifetime` doesn't matter much because Synapse doesn't take it into account yet. 
+
+* `allowed_lifetime_min` and `allowed_lifetime_max`: Retention policy limits. If 
+   set, and the state of a room contains a `m.room.retention` event in its state 
+   which contains a `min_lifetime` or a `max_lifetime` that's out of these bounds,
+   Synapse will cap the room's policy to these limits when running purge jobs.
+
+* `purge_jobs` and the associated `shortest_max_lifetime` and `longest_max_lifetime` sub-options:
+   Server admins can define the settings of the background jobs purging the
+   events whose lifetime has expired under the `purge_jobs` section.
+   
+  If no configuration is provided for this option, a single job will be set up to delete
+  expired events in every room daily.
+
+  Each job's configuration defines which range of message lifetimes the job
+  takes care of. For example, if `shortest_max_lifetime` is '2d' and
+  `longest_max_lifetime` is '3d', the job will handle purging expired events in
+  rooms whose state defines a `max_lifetime` that's both higher than 2 days, and
+  lower than or equal to 3 days. Both the minimum and the maximum value of a
+  range are optional, e.g. a job with no `shortest_max_lifetime` and a
+  `longest_max_lifetime` of '3d' will handle every room with a retention policy
+  whose `max_lifetime` is lower than or equal to three days.
+  
+  The rationale for this per-job configuration is that some rooms might have a
+  retention policy with a low `max_lifetime`, where history needs to be purged
+  of outdated messages on a more frequent basis than for the rest of the rooms
+  (e.g. every 12h), but not want that purge to be performed by a job that's
+  iterating over every room it knows, which could be heavy on the server.
+
+  If any purge job is configured, it is strongly recommended to have at least
+  a single job with neither `shortest_max_lifetime` nor `longest_max_lifetime`
+  set, or one job without `shortest_max_lifetime` and one job without
+  `longest_max_lifetime` set. Otherwise some rooms might be ignored, even if
+  `allowed_lifetime_min` and `allowed_lifetime_max` are set, because capping a
+  room's policy to these values is done after the policies are retrieved from
+  Synapse's database (which is done using the range specified in a purge job's
+  configuration).
+
+Example configuration:
+```yaml
+retention:
+  enabled: true
+  default_policy:
+    min_lifetime: 1d
+    max_lifetime: 1y
+  allowed_lifetime_min: 1d
+  allowed_lifetime_max: 1y
+  purge_jobs:
+    - longest_max_lifetime: 3d
+      interval: 12h
+    - shortest_max_lifetime: 3d
+      interval: 1d  
+```
+---
+## TLS ##
+
+Options related to TLS.
+
+---
+Config option: `tls_certificate_path`
+
+This option specifies a PEM-encoded X509 certificate for TLS.
+This certificate, as of Synapse 1.0, will need to be a valid and verifiable
+certificate, signed by a recognised Certificate Authority. Defaults to none. 
+
+Be sure to use a `.pem` file that includes the full certificate chain including
+any intermediate certificates (for instance, if using certbot, use
+`fullchain.pem` as your certificate, not `cert.pem`). 
+
+Example configuration:
+```yaml
+tls_certificate_path: "CONFDIR/SERVERNAME.tls.crt"
+```
+---
+Config option: `tls_private_key_path`
+
+PEM-encoded private key for TLS. Defaults to none. 
+
+Example configuration:
+```yaml
+tls_private_key_path: "CONFDIR/SERVERNAME.tls.key"
+```
+---
+Config option: `federation_verify_certificates`
+Whether to verify TLS server certificates for outbound federation requests.
+
+Defaults to true. To disable certificate verification, set the option to false.
+
+Example configuration:
+```yaml
+federation_verify_certificates: false
+```
+---
+Config option: `federation_client_minimum_tls_version`
+
+The minimum TLS version that will be used for outbound federation requests.
+
+Defaults to `1`. Configurable to `1`, `1.1`, `1.2`, or `1.3`. Note
+that setting this value higher than `1.2` will prevent federation to most
+of the public Matrix network: only configure it to `1.3` if you have an
+entirely private federation setup and you can ensure TLS 1.3 support.
+
+Example configuration:
+```yaml
+federation_client_minimum_tls_version: 1.2
+```
+---
+Config option: `federation_certificate_verification_whitelist`
+
+Skip federation certificate verification on a given whitelist
+of domains.
+
+This setting should only be used in very specific cases, such as
+federation over Tor hidden services and similar. For private networks
+of homeservers, you likely want to use a private CA instead.
+
+Only effective if `federation_verify_certicates` is `true`.
+
+Example configuration:
+```yaml
+federation_certificate_verification_whitelist:
+  - lon.example.com
+  - "*.domain.com"
+  - "*.onion"
+```
+---
+Config option: `federation_custom_ca_list`
+
+List of custom certificate authorities for federation traffic.
+
+This setting should only normally be used within a private network of
+homeservers.
+
+Note that this list will replace those that are provided by your
+operating environment. Certificates must be in PEM format.
+
+Example configuration:
+```yaml
+federation_custom_ca_list:
+  - myCA1.pem
+  - myCA2.pem
+  - myCA3.pem
+```
+---
+## Federation ##
+
+Options related to federation.
+
+---
+Config option: `federation_domain_whitelist`
+
+Restrict federation to the given whitelist of domains.
+N.B. we recommend also firewalling your federation listener to limit
+inbound federation traffic as early as possible, rather than relying
+purely on this application-layer restriction.  If not specified, the
+default is to whitelist everything.
+
+Example configuration:
+```yaml
+federation_domain_whitelist:
+  - lon.example.com
+  - nyc.example.com
+  - syd.example.com
+```
+---
+Config option: `federation_metrics_domains`
+
+Report prometheus metrics on the age of PDUs being sent to and received from
+the given domains. This can be used to give an idea of "delay" on inbound
+and outbound federation, though be aware that any delay can be due to problems
+at either end or with the intermediate network.
+
+By default, no domains are monitored in this way.
+
+Example configuration:
+```yaml
+federation_metrics_domains:
+  - matrix.org
+  - example.com
+```
+---
+Config option: `allow_profile_lookup_over_federation`
+
+Set to false to disable profile lookup over federation. By default, the
+Federation API allows other homeservers to obtain profile data of any user
+on this homeserver.
+
+Example configuration:
+```yaml
+allow_profile_lookup_over_federation: false
+```
+---
+Config option: `allow_device_name_lookup_over_federation`
+
+Set this option to false to disable device display name lookup over federation. By default, the
+Federation API allows other homeservers to obtain device display names of any user
+on this homeserver.
+
+Example configuration:
+```yaml
+allow_device_name_lookup_over_federation: false
+```
+---
+## Caching ##
+
+Options related to caching
+
+---
+Config option: `event_cache_size`
+
+The number of events to cache in memory. Not affected by
+`caches.global_factor`. Defaults to 10K.
+
+Example configuration:
+```yaml
+event_cache_size: 15K
+```
+---
+Config option: `cache` and associated values
+
+A cache 'factor' is a multiplier that can be applied to each of
+Synapse's caches in order to increase or decrease the maximum
+number of entries that can be stored.
+
+Caching can be configured through the following sub-options:
+
+* `global_factor`: Controls the global cache factor, which is the default cache factor
+  for all caches if a specific factor for that cache is not otherwise
+  set.
+
+  This can also be set by the `SYNAPSE_CACHE_FACTOR` environment
+  variable. Setting by environment variable takes priority over
+  setting through the config file.
+  
+  Defaults to 0.5, which will halve the size of all caches.
+
+* `per_cache_factors`: A dictionary of cache name to cache factor for that individual
+   cache. Overrides the global cache factor for a given cache.
+  
+   These can also be set through environment variables comprised
+   of `SYNAPSE_CACHE_FACTOR_` + the name of the cache in capital
+   letters and underscores. Setting by environment variable
+   takes priority over setting through the config file.
+   Ex. `SYNAPSE_CACHE_FACTOR_GET_USERS_WHO_SHARE_ROOM_WITH_USER=2.0`
+  
+   Some caches have '*' and other characters that are not
+   alphanumeric or underscores. These caches can be named with or
+   without the special characters stripped. For example, to specify
+   the cache factor for `*stateGroupCache*` via an environment
+   variable would be `SYNAPSE_CACHE_FACTOR_STATEGROUPCACHE=2.0`.
+ 
+* `expire_caches`: Controls whether cache entries are evicted after a specified time
+   period. Defaults to true. Set to false to disable this feature. Note that never expiring
+   caches may result in excessive memory usage. 
+
+* `cache_entry_ttl`: If `expire_caches` is enabled, this flag controls how long an entry can
+  be in a cache without having been accessed before being evicted.
+  Defaults to 30m. 
+
+* `sync_response_cache_duration`: Controls how long the results of a /sync request are
+  cached for after a successful response is returned. A higher duration can help clients
+  with intermittent connections, at the cost of higher memory usage.
+  By default, this is zero, which means that sync responses are not cached
+  at all.
+
+
+Example configuration:
+```yaml
+caches:
+  global_factor: 1.0
+  per_cache_factors:
+    get_users_who_share_room_with_user: 2.0
+  expire_caches: false
+  sync_response_cache_duration: 2m
+```
+---
+## Database ##
+Config options related to database settings.
+
+---
+Config option: `database`
+
+The `database` setting defines the database that synapse uses to store all of
+its data.
+
+Associated sub-options:
+
+* `name`: this option specifies the database engine to use: either `sqlite3` (for SQLite)
+  or `psycopg2` (for PostgreSQL). If no name is specified Synapse will default to SQLite. 
+
+* `txn_limit` gives the maximum number of transactions to run per connection
+  before reconnecting. Defaults to 0, which means no limit.
+
+* `allow_unsafe_locale` is an option specific to Postgres. Under the default behavior, Synapse will refuse to
+  start if the postgres db is set to a non-C locale. You can override this behavior (which is *not* recommended)
+  by setting `allow_unsafe_locale` to true. Note that doing so may corrupt your database. You can find more information
+  [here](../../postgres.md#fixing-incorrect-collate-or-ctype) and [here](https://wiki.postgresql.org/wiki/Locale_data_changes).
+
+* `args` gives options which are passed through to the database engine,
+  except for options starting with `cp_`, which are used to configure the Twisted
+  connection pool. For a reference to valid arguments, see:
+    * for [sqlite](https://docs.python.org/3/library/sqlite3.html#sqlite3.connect)
+    * for [postgres](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS)
+    * for [the connection pool](https://twistedmatrix.com/documents/current/api/twisted.enterprise.adbapi.ConnectionPool.html#__init__)
+
+For more information on using Synapse with Postgres,
+see [here](../../postgres.md).
+
+Example SQLite configuration:
+```
+database:
+  name: sqlite3
+  args:
+    database: /path/to/homeserver.db
+```
+
+Example Postgres configuration:
+```
+database:
+  name: psycopg2
+  txn_limit: 10000
+  args:
+    user: synapse_user
+    password: secretpassword
+    database: synapse
+    host: localhost
+    port: 5432
+    cp_min: 5
+    cp_max: 10
+```
+---
+## Logging ##
+Config options related to logging. 
+
+---
+Config option: `log_config`
+
+This option specifies a yaml python logging config file as described [here](https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema).
+
+Example configuration:
+```yaml
+log_config: "CONFDIR/SERVERNAME.log.config"
+```
+---
+## Ratelimiting ##
+Options related to ratelimiting in Synapse. 
+
+Each ratelimiting configuration is made of two parameters:
+   - `per_second`: number of requests a client can send per second.
+   - `burst_count`: number of requests a client can send before being throttled.
+---
+Config option: `rc_message`
+
+
+Ratelimiting settings for client messaging.
+   
+This is a ratelimiting option for messages that ratelimits sending based on the account the client
+is using. It defaults to: `per_second: 0.2`, `burst_count: 10`.
+
+Example configuration:
+```yaml
+rc_message:
+  per_second: 0.5
+  burst_count: 15
+```
+---
+Config option: `rc_registration`
+
+This option ratelimits registration requests based on the client's IP address.
+It defaults to `per_second: 0.17`, `burst_count: 3`. 
+
+Example configuration:
+```yaml
+rc_registration:
+  per_second: 0.15
+  burst_count: 2
+```
+---
+Config option: `rc_registration_token_validity`
+
+This option checks the validity of registration tokens that ratelimits requests based on 
+the client's IP address.
+Defaults to `per_second: 0.1`, `burst_count: 5`.
+
+Example configuration:
+```yaml
+rc_registration_token_validity:
+  per_second: 0.3
+  burst_count: 6
+```   
+---
+Config option: `rc_login`
+
+This option specifies several limits for login:
+* `address` ratelimits login requests based on the client's IP
+      address. Defaults to `per_second: 0.17`, `burst_count: 3`.
+    
+* `account` ratelimits login requests based on the account the
+  client is attempting to log into. Defaults to `per_second: 0.17`,
+  `burst_count: 3`.
+    
+* `failted_attempts` ratelimits login requests based on the account the
+  client is attempting to log into, based on the amount of failed login
+  attempts for this account. Defaults to `per_second: 0.17`, `burst_count: 3`.
+
+Example configuration:
+```yaml
+rc_login:
+  address:
+    per_second: 0.15
+    burst_count: 5
+  account:
+    per_second: 0.18
+    burst_count: 4
+  failed_attempts:
+    per_second: 0.19
+    burst_count: 7
+```
+---
+Config option: `rc_admin_redaction`
+
+This option sets ratelimiting redactions by room admins. If this is not explicitly 
+set then it uses the same ratelimiting as per `rc_message`. This is useful
+to allow room admins to deal with abuse quickly. 
+
+Example configuration:
+```yaml
+rc_admin_redaction:
+  per_second: 1
+  burst_count: 50
+```
+---
+Config option: `rc_joins`
+
+This option allows for ratelimiting number of rooms a user can join. This setting has the following sub-options:
+
+* `local`: ratelimits when users are joining rooms the server is already in. 
+   Defaults to `per_second: 0.1`, `burst_count: 10`.
+
+* `remote`: ratelimits when users are trying to join rooms not on the server (which
+  can be more computationally expensive than restricting locally). Defaults to
+  `per_second: 0.01`, `burst_count: 10` 
+
+Example configuration:
+```yaml
+rc_joins:
+  local:
+    per_second: 0.2
+    burst_count: 15
+  remote:
+    per_second: 0.03
+    burst_count: 12
+```
+---
+Config option: `rc_3pid_validation`
+
+This option ratelimits how often a user or IP can attempt to validate a 3PID.
+Defaults to `per_second: 0.003`, `burst_count: 5`.
+
+Example configuration:
+```yaml
+rc_3pid_validation:
+  per_second: 0.003
+  burst_count: 5
+```
+---
+Config option: `rc_invites`
+
+This option sets ratelimiting how often invites can be sent in a room or to a 
+specific user. `per_room` defaults to `per_second: 0.3`, `burst_count: 10` and
+`per_user` defaults to `per_second: 0.003`, `burst_count: 5`. 
+
+Example configuration:
+```yaml
+rc_invites:
+  per_room:
+    per_second: 0.5
+    burst_count: 5
+  per_user:
+    per_second: 0.004
+    burst_count: 3
+```
+---
+Config option: `rc_third_party_invite`
+
+This option ratelimits 3PID invites (i.e. invites sent to a third-party ID
+such as an email address or a phone number) based on the account that's
+sending the invite. Defaults to `per_second: 0.2`, `burst_count: 10`.
+
+Example configuration:
+```yaml
+rc_third_party_invite:
+  per_second: 0.2
+  burst_count: 10
+```
+---
+Config option: `rc_federation`
+
+Defines limits on federation requests. 
+
+The `rc_federation` configuration has the following sub-options:
+* `window_size`: window size in milliseconds. Defaults to 1000.
+* `sleep_limit`: number of federation requests from a single server in
+   a window before the server will delay processing the request. Defaults to 10.
+* `sleep_delay`: duration in milliseconds to delay processing events
+   from remote servers by if they go over the sleep limit. Defaults to 500.
+* `reject_limit`: maximum number of concurrent federation requests
+   allowed from a single server. Defaults to 50.
+* `concurrent`: number of federation requests to concurrently process
+   from a single server. Defaults to 3.
+
+Example configuration:
+```yaml
+rc_federation:
+  window_size: 750
+  sleep_limit: 15
+  sleep_delay: 400
+  reject_limit: 40
+  concurrent: 5
+```
+---
+Config option: `federation_rr_transactions_per_room_per_second`
+
+Sets outgoing federation transaction frequency for sending read-receipts,
+per-room.
+
+If we end up trying to send out more read-receipts, they will get buffered up
+into fewer transactions. Defaults to 50. 
+
+Example configuration:
+```yaml
+federation_rr_transactions_per_room_per_second: 40
+```
+---
+## Media Store ##
+Config options relating to Synapse media store.
+
+---
+Config option: `enable_media_repo` 
+
+Enable the media store service in the Synapse master. Defaults to true. 
+Set to false if you are using a separate media store worker.
+
+Example configuration:
+```yaml
+enable_media_repo: false
+```
+---
+Config option: `media_store_path`
+
+Directory where uploaded images and attachments are stored.
+
+Example configuration:
+```yaml
+media_store_path: "DATADIR/media_store"
+```
+---
+Config option: `media_storage_providers`
+
+Media storage providers allow media to be stored in different
+locations. Defaults to none. Associated sub-options are:
+* `module`: type of resource, e.g. `file_system`.
+* `store_local`: whether to store newly uploaded local files
+* `store_remote`: whether to store newly downloaded local files
+* `store_synchronous`: whether to wait for successful storage for local uploads
+* `config`: sets a path to the resource through the `directory` option 
+
+Example configuration:
+```yaml
+media_storage_providers:
+  - module: file_system
+    store_local: false
+    store_remote: false
+    store_synchronous: false
+    config:
+       directory: /mnt/some/other/directory
+```
+---
+Config option: `max_upload_size`
+
+The largest allowed upload size in bytes.
+
+If you are using a reverse proxy you may also need to set this value in
+your reverse proxy's config. Defaults to 50M. Notably Nginx has a small max body size by default.
+See [here](../../reverse_proxy.md) for more on using a reverse proxy with Synapse. 
+
+Example configuration:
+```yaml
+max_upload_size: 60M
+```
+---
+Config option: `max_image_pixels`
+
+Maximum number of pixels that will be thumbnailed. Defaults to 32M.
+
+Example configuration:
+```yaml
+max_image_pixels: 35M
+```
+---
+Config option: `dynamic_thumbnails`
+
+Whether to generate new thumbnails on the fly to precisely match
+the resolution requested by the client. If true then whenever
+a new resolution is requested by the client the server will
+generate a new thumbnail. If false the server will pick a thumbnail
+from a precalculated list. Defaults to false. 
+
+Example configuration:
+```yaml
+dynamic_thumbnails: true
+```
+---
+Config option: `thumbnail_sizes`  
+
+List of thumbnails to precalculate when an image is uploaded. Associated sub-options are:
+* `width`
+* `height`
+* `method`: i.e. `crop`, `scale`, etc.
+
+Example configuration:
+```yaml
+thumbnail_sizes:
+  - width: 32
+    height: 32
+    method: crop
+  - width: 96
+    height: 96
+    method: crop
+  - width: 320
+    height: 240
+    method: scale
+  - width: 640
+    height: 480
+    method: scale
+  - width: 800
+    height: 600
+    method: scale
+```
+Config option: `url_preview_enabled`
+
+This setting determines whether the preview URL API is enabled.
+It is disabled by default. Set to true to enable. If enabled you must specify a
+`url_preview_ip_range_blacklist` blacklist.
+
+Example configuration:
+```yaml
+url_preview_enabled: true
+```
+---
+Config option: `url_preview_ip_range_blacklist`
+
+List of IP address CIDR ranges that the URL preview spider is denied
+from accessing.  There are no defaults: you must explicitly
+specify a list for URL previewing to work.  You should specify any
+internal services in your network that you do not want synapse to try
+to connect to, otherwise anyone in any Matrix room could cause your
+synapse to issue arbitrary GET requests to your internal services,
+causing serious security issues.
+
+(0.0.0.0 and :: are always blacklisted, whether or not they are explicitly
+listed here, since they correspond to unroutable addresses.)
+
+This must be specified if `url_preview_enabled` is set. It is recommended that
+you use the following example list as a starting point.
+
+Note: The value is ignored when an HTTP proxy is in use.
+
+Example configuration:
+```yaml
+url_preview_ip_range_blacklist:
+  - '127.0.0.0/8'
+  - '10.0.0.0/8'
+  - '172.16.0.0/12'
+  - '192.168.0.0/16'
+  - '100.64.0.0/10'
+  - '192.0.0.0/24'
+  - '169.254.0.0/16'
+  - '192.88.99.0/24'
+  - '198.18.0.0/15'
+  - '192.0.2.0/24'
+  - '198.51.100.0/24'
+  - '203.0.113.0/24'
+  - '224.0.0.0/4'
+  - '::1/128'
+  - 'fe80::/10'
+  - 'fc00::/7'
+  - '2001:db8::/32'
+  - 'ff00::/8'
+  - 'fec0::/10'
+```
+----
+Config option: `url_preview_ip_range_whitelist`
+
+This option sets a list of IP address CIDR ranges that the URL preview spider is allowed
+to access even if they are specified in `url_preview_ip_range_blacklist`.
+This is useful for specifying exceptions to wide-ranging blacklisted
+target IP ranges - e.g. for enabling URL previews for a specific private
+website only visible in your network. Defaults to none. 
+
+Example configuration:
+```yaml
+url_preview_ip_range_whitelist:
+   - '192.168.1.1'
+```
+---
+Config option: `url_preview_url_blacklist`
+
+Optional list of URL matches that the URL preview spider is
+denied from accessing.  You should use `url_preview_ip_range_blacklist`
+in preference to this, otherwise someone could define a public DNS
+entry that points to a private IP address and circumvent the blacklist.
+This is more useful if you know there is an entire shape of URL that
+you know that will never want synapse to try to spider.
+
+Each list entry is a dictionary of url component attributes as returned
+by urlparse.urlsplit as applied to the absolute form of the URL.  See 
+[here](https://docs.python.org/2/library/urlparse.html#urlparse.urlsplit) for more
+information. Some examples are:
+
+* `username`
+* `netloc`
+* `scheme`
+* `path`
+
+The values of the dictionary are treated as a filename match pattern
+applied to that component of URLs, unless they start with a ^ in which
+case they are treated as a regular expression match.  If all the
+specified component matches for a given list item succeed, the URL is
+blacklisted.
+
+Example configuration:
+```yaml
+url_preview_url_blacklist:
+  # blacklist any URL with a username in its URI
+  - username: '*'
+
+  # blacklist all *.google.com URLs
+  - netloc: 'google.com'
+  - netloc: '*.google.com'
+
+  # blacklist all plain HTTP URLs
+  - scheme: 'http'
+
+  # blacklist http(s)://www.acme.com/foo
+  - netloc: 'www.acme.com'
+    path: '/foo'
+
+  # blacklist any URL with a literal IPv4 address
+  - netloc: '^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$'
+```
+---
+Config option: `max_spider_size`
+
+The largest allowed URL preview spidering size in bytes. Defaults to 10M.
+
+Example configuration:
+```yaml
+max_spider_size: 8M
+```
+---
+Config option: `url_preview_language`
+
+A list of values for the Accept-Language HTTP header used when
+downloading webpages during URL preview generation. This allows
+Synapse to specify the preferred languages that URL previews should
+be in when communicating with remote servers.
+
+Each value is a IETF language tag; a 2-3 letter identifier for a
+language, optionally followed by subtags separated by '-', specifying
+a country or region variant.
+
+Multiple values can be provided, and a weight can be added to each by
+using quality value syntax (;q=). '*' translates to any language.
+
+Defaults to "en".
+
+Example configuration:
+```yaml
+ url_preview_accept_language:
+   - en-UK
+   - en-US;q=0.9
+   - fr;q=0.8
+   - *;q=0.7
+```
+----
+Config option: `oembed`
+
+oEmbed allows for easier embedding content from a website. It can be
+used for generating URLs previews of services which support it. A default list of oEmbed providers
+is included with Synapse. Set `disable_default_providers` to true to disable using
+these default oEmbed URLs. Use `additional_providers` to specify additional files with oEmbed configuration (each 
+should be in the form of providers.json). By default this list is empty. 
+
+Example configuration:
+```yaml
+oembed:
+  disable_default_providers: true
+  additional_providers:
+    - oembed/my_providers.json
+```
+---
+## Captcha ##
+
+See [here](../../CAPTCHA_SETUP.md) for full details on setting up captcha.
+
+---
+Config option: `recaptcha_public_key`
+
+This homeserver's ReCAPTCHA public key. Must be specified if `enable_registration_captcha` is 
+enabled.
+
+Example configuration:
+```yaml
+recaptcha_public_key: "YOUR_PUBLIC_KEY"
+```
+---
+Config option: `recaptcha_private_key` 
+
+This homeserver's ReCAPTCHA private key. Must be specified if `enable_registration_captcha` is 
+enabled.
+
+Example configuration:
+```yaml
+recaptcha_private_key: "YOUR_PRIVATE_KEY"
+```
+---
+Config option: `enable_registration_captcha`
+
+Set to true to enable ReCaptcha checks when registering, preventing signup
+unless a captcha is answered. Requires a valid ReCaptcha public/private key. 
+Defaults to false.
+
+Example configuration:
+```yaml
+enable_registration_captcha: true
+```
+---
+Config option: `recaptcha_siteverify_api`
+
+The API endpoint to use for verifying `m.login.recaptcha` responses.
+Defaults to `https://www.recaptcha.net/recaptcha/api/siteverify`.
+
+Example configuration:
+```yaml
+recaptcha_siteverify_api: "https://my.recaptcha.site"
+```
+---
+## TURN ##
+Options related to adding a TURN server to Synapse.
+
+---
+Config option: `turn_uris`
+
+The public URIs of the TURN server to give to clients.
+
+Example configuration:
+```yaml
+turn_uris: [turn:example.org]
+```
+---
+Config option: `turn_shared_secret`
+
+The shared secret used to compute passwords for the TURN server.
+
+Example configuration:
+```yaml
+turn_shared_secret: "YOUR_SHARED_SECRET"
+```
+----
+Config options: `turn_username` and `turn_password`
+
+The Username and password if the TURN server needs them and does not use a token.
+
+Example configuration:
+```yaml
+turn_username: "TURNSERVER_USERNAME"
+turn_password: "TURNSERVER_PASSWORD"
+```
+---
+Config option: `turn_user_lifetime`
+
+How long generated TURN credentials last. Defaults to 1h.
+
+Example configuration:
+```yaml
+turn_user_lifetime: 2h
+```
+---
+Config option: `turn_allow_guests`
+
+Whether guests should be allowed to use the TURN server. This defaults to true, otherwise
+VoIP will be unreliable for guests. However, it does introduce a slight security risk as
+it allows users to connect to arbitrary endpoints without having first signed up for a valid account (e.g. by passing a CAPTCHA).
+
+Example configuration:
+```yaml
+turn_allow_guests: false
+```
+---
+## Registration ##
+
+Registration can be rate-limited using the parameters in the [Ratelimiting](#ratelimiting) section of this manual.
+
+---
+Config option: `enable_registration`
+
+Enable registration for new users. Defaults to false. It is highly recommended that if you enable registration,
+you use either captcha, email, or token-based verification to verify that new users are not bots. In order to enable registration 
+without any verification, you must also set `enable_registration_without_verification` to true.
+
+Example configuration:
+```yaml
+enable_registration: true
+```
+---
+Config option: `enable_registration_without_verification`
+Enable registration without email or captcha verification. Note: this option is *not* recommended,
+as registration without verification is a known vector for spam and abuse. Defaults to false. Has no effect
+unless `enable_registration` is also enabled.
+
+Example configuration:
+```yaml
+enable_registration_without_verification: true
+```
+---
+Config option: `session_lifetime`
+
+Time that a user's session remains valid for, after they log in.
+
+Note that this is not currently compatible with guest logins.
+
+Note also that this is calculated at login time: changes are not applied retrospectively to users who have already 
+logged in.
+
+By default, this is infinite.
+
+Example configuration:
+```yaml
+session_lifetime: 24h
+```
+----
+Config option: `refresh_access_token_lifetime`
+
+Time that an access token remains valid for, if the session is using refresh tokens.
+
+For more information about refresh tokens, please see the [manual](user_authentication/refresh_tokens.md).
+
+Note that this only applies to clients which advertise support for refresh tokens.
+
+Note also that this is calculated at login time and refresh time: changes are not applied to 
+existing sessions until they are refreshed.
+
+By default, this is 5 minutes.
+
+Example configuration:
+```yaml
+refreshable_access_token_lifetime: 10m
+```
+---
+Config option: `refresh_token_lifetime: 24h`
+
+Time that a refresh token remains valid for (provided that it is not
+exchanged for another one first).
+This option can be used to automatically log-out inactive sessions.
+Please see the manual for more information.
+
+Note also that this is calculated at login time and refresh time:
+changes are not applied to existing sessions until they are refreshed.
+
+By default, this is infinite.
+
+Example configuration:
+```yaml
+refresh_token_lifetime: 24h
+```
+---
+Config option: `nonrefreshable_access_token_lifetime`
+
+Time that an access token remains valid for, if the session is NOT
+using refresh tokens.
+
+Please note that not all clients support refresh tokens, so setting
+this to a short value may be inconvenient for some users who will
+then be logged out frequently.
+
+Note also that this is calculated at login time: changes are not applied
+retrospectively to existing sessions for users that have already logged in.
+
+By default, this is infinite.
+
+Example configuration:
+```yaml
+nonrefreshable_access_token_lifetime: 24h
+```
+---
+Config option: `registrations_require_3pid`
+
+If this is set, the user must provide all of the specified types of 3PID when registering.
+
+Example configuration:
+```yaml
+registrations_require_3pid:
+  - email
+  - msisdn
+```
+---
+Config option: `disable_msisdn_registration`
+
+Explicitly disable asking for MSISDNs from the registration
+flow (overrides `registrations_require_3pid` if MSISDNs are set as required).
+
+Example configuration:
+```yaml
+disable_msisdn_registration: true
+```
+---
+Config option: `allowed_local_3pids`
+
+Mandate that users are only allowed to associate certain formats of
+3PIDs with accounts on this server, as specified by the `medium` and `pattern` sub-options.
+
+Example configuration:
+```yaml
+allowed_local_3pids:
+  - medium: email
+    pattern: '^[^@]+@matrix\.org$'
+  - medium: email
+    pattern: '^[^@]+@vector\.im$'
+  - medium: msisdn
+    pattern: '\+44'
+```
+---
+Config option: `enable_3pid_lookup`
+
+Enable 3PIDs lookup requests to identity servers from this server. Defaults to true.
+
+Example configuration:
+```yaml
+enable_3pid_lookup: false
+```
+---
+Config option: `registration_requires_token`
+
+Require users to submit a token during registration.
+Tokens can be managed using the admin [API](../administration/admin_api/registration_tokens.md).
+Note that `enable_registration` must be set to true.
+Disabling this option will not delete any tokens previously generated.
+Defaults to false. Set to true to enable.  
+
+Example configuration:
+```yaml
+registration_requires_token: true
+```
+---
+Config option: `registration_shared_secret`
+
+If set, allows registration of standard or admin accounts by anyone who
+has the shared secret, even if registration is otherwise disabled.
+
+Example configuration:
+```yaml
+registration_shared_secret: <PRIVATE STRING>
+```
+---
+Config option: `bcrypt_rounds`
+
+Set the number of bcrypt rounds used to generate password hash.
+Larger numbers increase the work factor needed to generate the hash.
+The default number is 12 (which equates to 2^12 rounds).
+N.B. that increasing this will exponentially increase the time required
+to register or login - e.g. 24 => 2^24 rounds which will take >20 mins.
+Example configuration:
+```yaml
+bcrypt_rounds: 14
+```
+---
+Config option: `allow_guest_access`
+
+Allows users to register as guests without a password/email/etc, and
+participate in rooms hosted on this server which have been made
+accessible to anonymous users. Defaults to false.
+
+Example configuration:
+```yaml
+allow_guest_access: true
+```
+---
+Config option: `default_identity_server`
+
+The identity server which we suggest that clients should use when users log
+in on this server.
+
+(By default, no suggestion is made, so it is left up to the client.
+This setting is ignored unless `public_baseurl` is also explicitly set.)
+
+Example configuration:
+```yaml
+default_identity_server: https://matrix.org
+```
+---
+Config option: `account_threepid_delegates`
+
+Handle threepid (email/phone etc) registration and password resets through a set of
+*trusted* identity servers. Note that this allows the configured identity server to
+reset passwords for accounts!
+
+Be aware that if `email` is not set, and SMTP options have not been
+configured in the email config block, registration and user password resets via
+email will be globally disabled.
+
+Additionally, if `msisdn` is not set, registration and password resets via msisdn
+will be disabled regardless, and users will not be able to associate an msisdn
+identifier to their account. This is due to Synapse currently not supporting
+any method of sending SMS messages on its own.
+
+To enable using an identity server for operations regarding a particular third-party
+identifier type, set the value to the URL of that identity server as shown in the
+examples below.
+
+Servers handling the these requests must answer the `/requestToken` endpoints defined
+by the Matrix Identity Service API [specification](https://matrix.org/docs/spec/identity_service/latest).
+
+Example configuration:
+```yaml
+account_threepid_delegates:
+    email: https://example.com     # Delegate email sending to example.com
+    msisdn: http://localhost:8090  # Delegate SMS sending to this local process
+```
+---
+Config option: `enable_set_displayname`
+
+Whether users are allowed to change their displayname after it has
+been initially set. Useful when provisioning users based on the
+contents of a third-party directory.
+
+Does not apply to server administrators. Defaults to true.
+
+Example configuration:
+```yaml
+enable_set_displayname: false
+```
+---
+Config option: `enable_set_avatar_url`
+
+Whether users are allowed to change their avatar after it has been
+initially set. Useful when provisioning users based on the contents
+of a third-party directory.
+
+Does not apply to server administrators. Defaults to true.
+
+Example configuration:
+```yaml
+enable_set_avatar_url: false
+```
+---
+Config option: `enable_3pid_changes`
+
+Whether users can change the third-party IDs associated with their accounts
+(email address and msisdn).
+
+Defaults to true.
+
+Example configuration:
+```yaml
+enable_3pid_changes: false
+```
+---
+Config option: `auto_join_rooms`
+
+Users who register on this homeserver will automatically be joined
+to the rooms listed under this option.
+
+By default, any room aliases included in this list will be created
+as a publicly joinable room when the first user registers for the
+homeserver. If the room already exists, make certain it is a publicly joinable
+room, i.e. the join rule of the room must be set to 'public'. You can find more options
+relating to auto-joining rooms below. 
+
+Example configuration:
+```yaml
+auto_join_rooms:
+  - "#exampleroom:example.com"
+  - "#anotherexampleroom:example.com"
+```
+---
+Config option: `autocreate_auto_join_rooms`
+
+Where `auto_join_rooms` are specified, setting this flag ensures that
+the rooms exist by creating them when the first user on the
+homeserver registers.
+
+By default the auto-created rooms are publicly joinable from any federated
+server. Use the `autocreate_auto_join_rooms_federated` and
+`autocreate_auto_join_room_preset` settings to customise this behaviour.
+
+Setting to false means that if the rooms are not manually created,
+users cannot be auto-joined since they do not exist.
+
+Defaults to true.
+
+Example configuration:
+```yaml
+autocreate_auto_join_rooms: false
+```
+---
+Config option: `autocreate_auto_join_rooms_federated`
+
+Whether the rooms listen in `auto_join_rooms` that are auto-created are available
+via federation. Only has an effect if `autocreate_auto_join_rooms` is true.
+
+Note that whether a room is federated cannot be modified after
+creation.
+
+Defaults to true: the room will be joinable from other servers.
+Set to false to prevent users from other homeservers from
+joining these rooms.
+
+Example configuration:
+```yaml
+autocreate_auto_join_rooms_federated: false
+```
+---
+Config option: `autocreate_auto_join_room_preset`
+
+The room preset to use when auto-creating one of `auto_join_rooms`. Only has an
+effect if `autocreate_auto_join_rooms` is true.
+
+Possible values for this option are:
+* "public_chat": the room is joinable by anyone, including
+  federated servers if `autocreate_auto_join_rooms_federated` is true (the default).
+* "private_chat": an invitation is required to join these rooms. 
+* "trusted_private_chat": an invitation is required to join this room and the invitee is
+  assigned a power level of 100 upon joining the room. 
+
+If a value of "private_chat" or "trusted_private_chat" is used then
+`auto_join_mxid_localpart` must also be configured.
+
+Defaults to "public_chat".
+
+Example configuration:
+```yaml
+autocreate_auto_join_room_preset: private_chat
+```
+---
+Config option: `auto_join_mxid_localpart`
+
+The local part of the user id which is used to create `auto_join_rooms` if
+`autocreate_auto_join_rooms` is true. If this is not provided then the
+initial user account that registers will be used to create the rooms.
+
+The user id is also used to invite new users to any auto-join rooms which
+are set to invite-only.
+
+It *must* be configured if `autocreate_auto_join_room_preset` is set to
+"private_chat" or "trusted_private_chat".
+
+Note that this must be specified in order for new users to be correctly
+invited to any auto-join rooms which have been set to invite-only (either
+at the time of creation or subsequently).
+
+Note that, if the room already exists, this user must be joined and
+have the appropriate permissions to invite new members.
+
+Example configuration:
+```yaml
+auto_join_mxid_localpart: system
+```
+---
+Config option: `auto_join_rooms_for_guests`
+ 
+When `auto_join_rooms` is specified, setting this flag to false prevents
+guest accounts from being automatically joined to the rooms.
+
+Defaults to true.
+
+Example configuration:
+```yaml
+auto_join_rooms_for_guests: false
+```
+---
+Config option: `inhibit_user_in_use_error`
+ 
+Whether to inhibit errors raised when registering a new account if the user ID
+already exists. If turned on, requests to `/register/available` will always
+show a user ID as available, and Synapse won't raise an error when starting
+a registration with a user ID that already exists. However, Synapse will still
+raise an error if the registration completes and the username conflicts.
+
+Defaults to false.
+
+Example configuration:
+```yaml
+inhibit_user_in_use_error: true
+```
+---
+## Metrics ###
+Config options related to metrics.
+
+---
+Config option: `enable_metrics`
+
+Set to true to enable collection and rendering of performance metrics. 
+Defaults to false.
+
+Example configuration:
+```yaml
+enable_metrics: true
+```
+---
+Config option: `sentry`
+
+Use this option to enable sentry integration. Provide the DSN assigned to you by sentry
+with the `dsn` setting. 
+
+NOTE: While attempts are made to ensure that the logs don't contain
+any sensitive information, this cannot be guaranteed. By enabling
+this option the sentry server may therefore receive sensitive 
+information, and it in turn may then disseminate sensitive information
+through insecure notification channels if so configured.
+
+Example configuration:
+```yaml
+sentry:
+    dsn: "..."
+```
+---
+Config option: `metrics_flags`
+
+Flags to enable Prometheus metrics which are not suitable to be
+enabled by default, either for performance reasons or limited use.
+Currently the only option is `known_servers`, which publishes 
+`synapse_federation_known_servers`, a gauge of the number of
+servers this homeserver knows about, including itself. May cause
+performance problems on large homeservers.
+
+Example configuration:
+```yaml
+metrics_flags:
+    known_servers: true
+```
+---
+Config option: `report_stats`
+
+Whether or not to report anonymized homeserver usage statistics. This is originally
+set when generating the config. Set this option to true or false to change the current
+behavior. 
+
+Example configuration:
+```yaml
+report_stats: true
+```
+---
+Config option: `report_stats_endpoint`
+
+The endpoint to report the anonymized homeserver usage statistics to.
+Defaults to https://matrix.org/report-usage-stats/push
+
+Example configuration:
+```yaml
+report_stats_endpoint: https://example.com/report-usage-stats/push
+```
+---
+## API Configuration ##
+Config settings related to the client/server API
+
+---
+Config option: `room_prejoin_state:`
+
+Controls for the state that is shared with users who receive an invite
+to a room. By default, the following state event types are shared with users who 
+receive invites to the room:
+- m.room.join_rules
+- m.room.canonical_alias
+- m.room.avatar
+- m.room.encryption
+- m.room.name
+- m.room.create
+- m.room.topic
+
+To change the default behavior, use the following sub-options:
+* `disable_default_event_types`: set to true to disable the above defaults. If this 
+   is enabled, only the event types listed in `additional_event_types` are shared.
+   Defaults to false.
+* `additional_event_types`: Additional state event types to share with users when they are invited
+   to a room. By default, this list is empty (so only the default event types are shared).
+
+Example configuration:
+```yaml
+room_prejoin_state:
+   disable_default_event_types: true
+   additional_event_types:
+     - org.example.custom.event.type
+     - m.room.join_rules
+```
+---
+Config option: `track_puppeted_user_ips`
+
+We record the IP address of clients used to access the API for various
+reasons, including displaying it to the user in the "Where you're signed in"
+dialog.
+
+By default, when puppeting another user via the admin API, the client IP
+address is recorded against the user who created the access token (ie, the
+admin user), and *not* the puppeted user.
+
+Set this option to true to also record the IP address against the puppeted
+user. (This also means that the puppeted user will count as an "active" user
+for the purpose of monthly active user tracking - see `limit_usage_by_mau` etc
+above.)
+
+Example configuration:
+```yaml
+track_puppeted_user_ips: true
+```
+---
+Config option: `app_service_config_files`
+
+A list of application service config files to use.
+
+Example configuration:
+```yaml
+app_service_config_files:
+  - app_service_1.yaml
+  - app_service_2.yaml
+```
+---
+Config option: `track_appservice_user_ips`
+
+Defaults to false. Set to true to enable tracking of application service IP addresses.
+Implicitly enables MAU tracking for application service users.
+
+Example configuration:
+```yaml
+track_appservice_user_ips: true
+```
+---
+Config option: `macaroon_secret_key`
+
+A secret which is used to sign access tokens. If none is specified,
+the `registration_shared_secret` is used, if one is given; otherwise,
+a secret key is derived from the signing key.
+
+Example configuration:
+```yaml
+macaroon_secret_key: <PRIVATE STRING>
+```
+---
+Config option: `form_secret`
+
+A secret which is used to calculate HMACs for form values, to stop
+falsification of values. Must be specified for the User Consent
+forms to work.
+
+Example configuration:
+```yaml
+form_secret: <PRIVATE STRING>
+```
+---
+## Signing Keys ##
+Config options relating to signing keys
+
+---
+Config option: `signing_key_path`
+
+Path to the signing key to sign messages with.
+
+Example configuration:
+```yaml
+signing_key_path: "CONFDIR/SERVERNAME.signing.key"
+```
+--- 
+Config option: `old_signing_keys`
+
+The keys that the server used to sign messages with but won't use
+to sign new messages. For each key, `key` should be the base64-encoded public key, and
+`expired_ts`should be the time (in milliseconds since the unix epoch) that
+it was last used.
+
+It is possible to build an entry from an old `signing.key` file using the
+`export_signing_key` script which is provided with synapse.
+
+Example configuration:
+```yaml
+old_signing_keys:
+  "ed25519:id": { key: "base64string", expired_ts: 123456789123 }
+```
+---
+Config option: `key_refresh_interval`
+
+How long key response published by this server is valid for.
+Used to set the `valid_until_ts` in `/key/v2` APIs.
+Determines how quickly servers will query to check which keys
+are still valid. Defaults to 1d.
+
+Example configuration:
+```yaml
+key_refresh_interval: 2d
+```
+---
+Config option: `trusted_key_servers:`
+
+The trusted servers to download signing keys from.
+
+When we need to fetch a signing key, each server is tried in parallel.
+
+Normally, the connection to the key server is validated via TLS certificates.
+Additional security can be provided by configuring a `verify key`, which
+will make synapse check that the response is signed by that key.
+
+This setting supercedes an older setting named `perspectives`. The old format
+is still supported for backwards-compatibility, but it is deprecated.
+
+`trusted_key_servers` defaults to matrix.org, but using it will generate a
+warning on start-up. To suppress this warning, set
+`suppress_key_server_warning` to true.
+
+Options for each entry in the list include:
+* `server_name`: the name of the server. Required.
+* `verify_keys`: an optional map from key id to base64-encoded public key.
+   If specified, we will check that the response is signed by at least
+   one of the given keys.
+* `accept_keys_insecurely`: a boolean. Normally, if `verify_keys` is unset,
+   and `federation_verify_certificates` is not `true`, synapse will refuse 
+   to start, because this would allow anyone who can spoof DNS responses
+   to masquerade as the trusted key server. If you know what you are doing
+   and are sure that your network environment provides a secure connection
+   to the key server, you can set this to `true` to override this behaviour.
+
+Example configuration #1:
+```yaml
+trusted_key_servers:
+  - server_name: "my_trusted_server.example.com"
+    verify_keys:
+      "ed25519:auto": "abcdefghijklmnopqrstuvwxyzabcdefghijklmopqr"
+  - server_name: "my_other_trusted_server.example.com"
+```
+Example configuration #2:
+```yaml
+trusted_key_servers:
+  - server_name: "matrix.org"
+```
+---
+Config option: `suppress_key_server_warning`
+
+Set the following to true to disable the warning that is emitted when the
+`trusted_key_servers` include 'matrix.org'. See above.
+
+Example configuration:
+```yaml
+suppress_key_server_warning: true
+```
+---
+Config option: `key_server_signing_keys_path`
+
+The signing keys to use when acting as a trusted key server. If not specified
+defaults to the server signing key.
+
+Can contain multiple keys, one per line.
+
+Example configuration:
+```yaml
+key_server_signing_keys_path: "key_server_signing_keys.key"
+```
+---
+## Single sign-on integration ##
+
+The following settings can be used to make Synapse use a single sign-on
+provider for authentication, instead of its internal password database.
+
+You will probably also want to set the following options to false to
+disable the regular login/registration flows:
+   * `enable_registration`
+   * `password_config.enabled`
+
+You will also want to investigate the settings under the "sso" configuration
+section below.
+
+---
+Config option: `saml2_config`
+
+Enable SAML2 for registration and login. Uses pysaml2. To learn more about pysaml and
+to find a full list options for configuring pysaml, read the docs [here](https://pysaml2.readthedocs.io/en/latest/).
+
+At least one of `sp_config` or `config_path` must be set in this section to
+enable SAML login. You can either put your entire pysaml config inline using the `sp_config`
+option, or you can specify a path to a psyaml config file with the sub-option `config_path`.
+This setting has the following sub-options:
+
+* `sp_config`: the configuration for the pysaml2 Service Provider. See pysaml2 docs for format of config.
+   Default values will be used for the `entityid` and `service` settings,
+   so it is not normally necessary to specify them unless you need to
+   override them. Here are a few useful sub-options for configuring pysaml:
+   * `metadata`: Point this to the IdP's metadata. You must provide either a local
+      file via the `local` attribute or (preferably) a URL via the
+      `remote` attribute.
+   * `accepted_time_diff: 3`: Allowed clock difference in seconds between the homeserver and IdP.
+      Defaults to 0.
+   * `service`: By default, the user has to go to our login page first. If you'd like
+     to allow IdP-initiated login, set `allow_unsolicited` to true under `sp` in the `service`
+     section.
+* `config_path`: specify a separate pysaml2 configuration file thusly: 
+  `config_path: "CONFDIR/sp_conf.py"`
+* `saml_session_lifetime`: The lifetime of a SAML session. This defines how long a user has to
+   complete the authentication process, if `allow_unsolicited` is unset. The default is 15 minutes.
+* `user_mapping_provider`: Using this option, an external module can be provided as a 
+   custom solution to mapping attributes returned from a saml provider onto a matrix user. The 
+   `user_mapping_provider` has the following attributes:
+  * `module`: The custom module's class. 
+  * `config`: Custom configuration values for the module. Use the values provided in the 
+     example if you are using the built-in user_mapping_provider, or provide your own
+     config values for a custom class if you are using one. This section will be passed as a Python
+     dictionary to the module's `parse_config` method. The built-in provider takes the following two
+     options:
+      * `mxid_source_attribute`: The SAML attribute (after mapping via the attribute maps) to use
+          to derive the Matrix ID from. It is 'uid' by default. Note: This used to be configured by the
+          `saml2_config.mxid_source_attribute option`. If that is still defined, its value will be used instead.
+      * `mxid_mapping`: The mapping system to use for mapping the saml attribute onto a
+         matrix ID. Options include: `hexencode` (which maps unpermitted characters to '=xx')
+         and `dotreplace` (which replaces unpermitted characters with '.').
+         The default is `hexencode`. Note: This used to be configured by the
+         `saml2_config.mxid_mapping option`. If that is still defined, its value will be used instead.
+* `grandfathered_mxid_source_attribute`: In previous versions of synapse, the mapping from SAML attribute to
+   MXID was always calculated dynamically rather than stored in a table. For backwards- compatibility, we will look for `user_ids`
+   matching such a pattern before creating a new account. This setting controls the SAML attribute which will be used for this
+   backwards-compatibility lookup. Typically it should be 'uid', but if the attribute maps are changed, it may be necessary to change it.
+   The default is 'uid'. 
+* `attribute_requirements`: It is possible to configure Synapse to only allow logins if SAML attributes
+    match particular values. The requirements can be listed under
+   `attribute_requirements` as shown in the example. All of the listed attributes must
+    match for the login to be permitted.
+* `idp_entityid`: If the metadata XML contains multiple IdP entities then the `idp_entityid`
+   option must be set to the entity to redirect users to.
+   Most deployments only have a single IdP entity and so should omit this option.
+  
+
+Once SAML support is enabled, a metadata file will be exposed at
+`https://<server>:<port>/_synapse/client/saml2/metadata.xml`, which you may be able to
+use to configure your SAML IdP with. Alternatively, you can manually configure
+the IdP to use an ACS location of
+`https://<server>:<port>/_synapse/client/saml2/authn_response`.
+
+Example configuration:
+```yaml
+saml2_config:
+  sp_config:
+    metadata:
+      local: ["saml2/idp.xml"]
+      remote:
+        - url: https://our_idp/metadata.xml
+    accepted_time_diff: 3
+
+    service:
+      sp:
+        allow_unsolicited: true
+
+    # The examples below are just used to generate our metadata xml, and you
+    # may well not need them, depending on your setup. Alternatively you
+    # may need a whole lot more detail - see the pysaml2 docs!
+    description: ["My awesome SP", "en"]
+    name: ["Test SP", "en"]
+
+    ui_info:
+      display_name:
+        - lang: en
+          text: "Display Name is the descriptive name of your service."
+      description:
+        - lang: en
+          text: "Description should be a short paragraph explaining the purpose of the service."
+      information_url:
+        - lang: en
+          text: "https://example.com/terms-of-service"
+      privacy_statement_url:
+        - lang: en
+          text: "https://example.com/privacy-policy"
+      keywords:
+        - lang: en
+          text: ["Matrix", "Element"]
+      logo:
+        - lang: en
+          text: "https://example.com/logo.svg"
+          width: "200"
+          height: "80"
+
+    organization:
+      name: Example com
+      display_name:
+        - ["Example co", "en"]
+      url: "http://example.com"
+
+    contact_person:
+      - given_name: Bob
+        sur_name: "the Sysadmin"
+        email_address": ["admin@example.com"]
+        contact_type": technical
+        
+  saml_session_lifetime: 5m
+  
+  user_mapping_provider:
+    # Below options are intended for the built-in provider, they should be 
+    # changed if using a custom module. 
+    config:
+      mxid_source_attribute: displayName
+      mxid_mapping: dotreplace
+  
+  grandfathered_mxid_source_attribute: upn
+
+  attribute_requirements:
+    - attribute: userGroup
+      value: "staff"
+    - attribute: department
+      value: "sales"
+
+  idp_entityid: 'https://our_idp/entityid'
+```
+---
+Config option: `oidc_providers`
+
+List of OpenID Connect (OIDC) / OAuth 2.0 identity providers, for registration
+and login. See [here](../../openid.md)
+for information on how to configure these options.
+
+For backwards compatibility, it is also possible to configure a single OIDC
+provider via an `oidc_config` setting. This is now deprecated and admins are
+advised to migrate to the `oidc_providers` format. (When doing that migration,
+use `oidc` for the `idp_id` to ensure that existing users continue to be
+recognised.)
+
+Options for each entry include:
+* `idp_id`: a unique identifier for this identity provider. Used internally
+   by Synapse; should be a single word such as 'github'.
+   Note that, if this is changed, users authenticating via that provider
+   will no longer be recognised as the same user!
+   (Use "oidc" here if you are migrating from an old `oidc_config` configuration.)
+
+* `idp_name`: A user-facing name for this identity provider, which is used to
+   offer the user a choice of login mechanisms.
+
+* `idp_icon`: An optional icon for this identity provider, which is presented
+   by clients and Synapse's own IdP picker page. If given, must be an
+   MXC URI of the format mxc://<server-name>/<media-id>. (An easy way to
+   obtain such an MXC URI is to upload an image to an (unencrypted) room
+   and then copy the "url" from the source of the event.)
+
+* `idp_brand`: An optional brand for this identity provider, allowing clients
+   to style the login flow according to the identity provider in question.
+   See the [spec](https://spec.matrix.org/latest/) for possible options here.
+
+* `discover`: set to false to disable the use of the OIDC discovery mechanism
+  to discover endpoints. Defaults to true.
+
+* `issuer`: Required. The OIDC issuer. Used to validate tokens and (if discovery
+   is enabled) to discover the provider's endpoints.
+
+* `client_id`: Required. oauth2 client id to use.
+
+* `client_secret`: oauth2 client secret to use. May be omitted if
+  `client_secret_jwt_key` is given, or if `client_auth_method` is 'none'.
+
+* `client_secret_jwt_key`: Alternative to client_secret: details of a key used
+   to create a JSON Web Token to be used as an OAuth2 client secret. If
+   given, must be a dictionary with the following properties:
+
+  * `key`: a pem-encoded signing key. Must be a suitable key for the
+    algorithm specified. Required unless `key_file` is given.
+
+  * `key_file`: the path to file containing a pem-encoded signing key file.
+     Required unless `key` is given.
+
+  * `jwt_header`: a dictionary giving properties to include in the JWT
+     header. Must include the key `alg`, giving the algorithm used to
+     sign the JWT, such as "ES256", using the JWA identifiers in
+     RFC7518.
+
+  * `jwt_payload`: an optional dictionary giving properties to include in
+    the JWT payload. Normally this should include an `iss` key.
+
+* `client_auth_method`: auth method to use when exchanging the token. Valid
+   values are `client_secret_basic` (default), `client_secret_post` and
+   `none`.
+
+* `scopes`: list of scopes to request. This should normally include the "openid"
+   scope. Defaults to ["openid"].
+
+* `authorization_endpoint`: the oauth2 authorization endpoint. Required if
+   provider discovery is disabled.
+
+* `token_endpoint`: the oauth2 token endpoint. Required if provider discovery is
+   disabled.
+
+* `userinfo_endpoint`: the OIDC userinfo endpoint. Required if discovery is
+   disabled and the 'openid' scope is not requested.
+
+* `jwks_uri`: URI where to fetch the JWKS. Required if discovery is disabled and
+   the 'openid' scope is used.
+
+* `skip_verification`: set to 'true' to skip metadata verification. Use this if
+   you are connecting to a provider that is not OpenID Connect compliant.
+   Defaults to false. Avoid this in production.
+
+* `user_profile_method`: Whether to fetch the user profile from the userinfo
+   endpoint, or to rely on the data returned in the id_token from the `token_endpoint`.
+   Valid values are: `auto` or `userinfo_endpoint`.
+   Defaults to `auto`, which uses the userinfo endpoint if `openid` is
+   not included in `scopes`. Set to `userinfo_endpoint` to always use the
+   userinfo endpoint.
+
+* `allow_existing_users`: set to true to allow a user logging in via OIDC to
+   match a pre-existing account instead of failing. This could be used if
+   switching from password logins to OIDC. Defaults to false.
+
+* `user_mapping_provider`: Configuration for how attributes returned from a OIDC
+   provider are mapped onto a matrix user. This setting has the following
+   sub-properties:
+
+     * `module`: The class name of a custom mapping module. Default is
+       `synapse.handlers.oidc.JinjaOidcMappingProvider`.
+        See https://matrix-org.github.io/synapse/latest/sso_mapping_providers.html#openid-mapping-providers
+        for information on implementing a custom mapping provider.
+
+     * `config`: Configuration for the mapping provider module. This section will
+        be passed as a Python dictionary to the user mapping provider
+        module's `parse_config` method.
+
+        For the default provider, the following settings are available:
+
+       * subject_claim: name of the claim containing a unique identifier
+         for the user. Defaults to 'sub', which OpenID Connect
+         compliant providers should provide.
+
+       * `localpart_template`: Jinja2 template for the localpart of the MXID.
+          If this is not set, the user will be prompted to choose their
+          own username (see the documentation for the `sso_auth_account_details.html` 
+          template). This template can use the `localpart_from_email` filter.
+
+       * `confirm_localpart`: Whether to prompt the user to validate (or
+          change) the generated localpart (see the documentation for the
+          'sso_auth_account_details.html' template), instead of
+          registering the account right away.
+
+       * `display_name_template`: Jinja2 template for the display name to set
+          on first login. If unset, no displayname will be set.
+
+       * `email_template`: Jinja2 template for the email address of the user.
+          If unset, no email address will be added to the account.
+                 
+       * `extra_attributes`: a map of Jinja2 templates for extra attributes
+          to send back to the client during login. Note that these are non-standard and clients will ignore them
+          without modifications.
+
+     When rendering, the Jinja2 templates are given a 'user' variable,
+     which is set to the claims returned by the UserInfo Endpoint and/or
+     in the ID Token.
+
+
+It is possible to configure Synapse to only allow logins if certain attributes 
+match particular values in the OIDC userinfo. The requirements can be listed under
+`attribute_requirements` as shown here:
+```yaml
+attribute_requirements:
+     - attribute: family_name
+       value: "Stephensson"
+     - attribute: groups
+       value: "admin"
+```
+All of the listed attributes must match for the login to be permitted. Additional attributes can be added to
+userinfo by expanding the `scopes` section of the OIDC config to retrieve
+additional information from the OIDC provider.
+
+If the OIDC claim is a list, then the attribute must match any value in the list.
+Otherwise, it must exactly match the value of the claim. Using the example 
+above, the `family_name` claim MUST be "Stephensson", but the `groups`
+claim MUST contain "admin".
+
+Example configuration:
+```yaml
+oidc_providers:
+  # Generic example
+  #
+  - idp_id: my_idp
+    idp_name: "My OpenID provider"
+    idp_icon: "mxc://example.com/mediaid"
+    discover: false
+    issuer: "https://accounts.example.com/"
+    client_id: "provided-by-your-issuer"
+    client_secret: "provided-by-your-issuer"
+    client_auth_method: client_secret_post
+    scopes: ["openid", "profile"]
+    authorization_endpoint: "https://accounts.example.com/oauth2/auth"
+    token_endpoint: "https://accounts.example.com/oauth2/token"
+    userinfo_endpoint: "https://accounts.example.com/userinfo"
+    jwks_uri: "https://accounts.example.com/.well-known/jwks.json"
+    skip_verification: true
+    user_mapping_provider:
+      config:
+        subject_claim: "id"
+        localpart_template: "{{ user.login }}"
+        display_name_template: "{{ user.name }}"
+        email_template: "{{ user.email }}"
+    attribute_requirements:
+      - attribute: userGroup
+        value: "synapseUsers"
+```
+---
+Config option: `cas_config`
+
+Enable Central Authentication Service (CAS) for registration and login.
+Has the following sub-options:
+* `enabled`: Set this to true to enable authorization against a CAS server.
+   Defaults to false.
+* `server_url`: The URL of the CAS authorization endpoint.
+* `displayname_attribute`: The attribute of the CAS response to use as the display name.
+   If no name is given here, no displayname will be set.
+* `required_attributes`:  It is possible to configure Synapse to only allow logins if CAS attributes
+   match particular values. All of the keys given below must exist
+   and the values must match the given value. Alternately if the given value
+   is `None` then any value is allowed (the attribute just must exist).
+   All of the listed attributes must match for the login to be permitted.
+
+Example configuration:
+```yaml
+cas_config:
+  enabled: true
+  server_url: "https://cas-server.com"
+  displayname_attribute: name
+  required_attributes:
+    userGroup: "staff"
+    department: None
+```
+---
+Config option: `sso`
+
+Additional settings to use with single-sign on systems such as OpenID Connect,
+SAML2 and CAS.
+
+Server admins can configure custom templates for pages related to SSO. See 
+[here](../../templates.md) for more information.
+
+Options include:
+* `client_whitelist`: A list of client URLs which are whitelisted so that the user does not
+   have to confirm giving access to their account to the URL. Any client
+   whose URL starts with an entry in the following list will not be subject
+   to an additional confirmation step after the SSO login is completed.
+   WARNING: An entry such as "https://my.client" is insecure, because it
+   will also match "https://my.client.evil.site", exposing your users to
+   phishing attacks from evil.site. To avoid this, include a slash after the
+   hostname: "https://my.client/".
+   The login fallback page (used by clients that don't natively support the
+   required login flows) is whitelisted in addition to any URLs in this list.
+   By default, this list contains only the login fallback page.
+* `update_profile_information`: Use this setting to keep a user's profile fields in sync with information from
+   the identity provider. Currently only syncing the displayname is supported. Fields 
+   are checked on every SSO login, and are updated if necessary.
+   Note that enabling this option will override user profile information,
+   regardless of whether users have opted-out of syncing that
+   information when first signing in. Defaults to false.
+
+
+Example configuration:
+```yaml
+sso:
+    client_whitelist:
+      - https://riot.im/develop
+      - https://my.custom.client/
+    update_profile_information: true
+```
+---
+Config option: `jwt_config`
+
+JSON web token integration. The following settings can be used to make
+Synapse JSON web tokens for authentication, instead of its internal
+password database.
+
+Each JSON Web Token needs to contain a "sub" (subject) claim, which is
+used as the localpart of the mxid.
+
+Additionally, the expiration time ("exp"), not before time ("nbf"),
+and issued at ("iat") claims are validated if present.
+
+Note that this is a non-standard login type and client support is
+expected to be non-existent.
+
+See [here](../../jwt.md) for more.
+
+Additional sub-options for this setting include:
+* `enabled`: Set to true to enable authorization using JSON web
+   tokens. Defaults to false.
+* `secret`: This is either the private shared secret or the public key used to
+   decode the contents of the JSON web token. Required if `enabled` is set to true.
+* `algorithm`: The algorithm used to sign the JSON web token. Supported algorithms are listed at
+   https://pyjwt.readthedocs.io/en/latest/algorithms.html Required if `enabled` is set to true.
+* `subject_claim`: Name of the claim containing a unique identifier for the user.
+   Optional, defaults to `sub`.
+* `issuer`: The issuer to validate the "iss" claim against. Optional. If provided the 
+   "iss" claim will be required and validated for all JSON web tokens.
+* `audiences`: A list of audiences to validate the "aud" claim against. Optional.
+   If provided the "aud" claim will be required and validated for all JSON web tokens.
+   Note that if the "aud" claim is included in a JSON web token then
+   validation will fail without configuring audiences.
+
+Example configuration:
+```yaml
+jwt_config:
+    enabled: true 
+    secret: "provided-by-your-issuer"
+    algorithm: "provided-by-your-issuer"
+    subject_claim: "name_of_claim"
+    issuer: "provided-by-your-issuer"
+    audiences:
+        - "provided-by-your-issuer"
+```
+---
+Config option: `password_config`
+
+Use this setting to enable password-based logins. 
+
+This setting has the following sub-options:
+* `enabled`: Defaults to true.
+* `localdb_enabled`: Set to false to disable authentication against the local password
+   database. This is ignored if `enabled` is false, and is only useful
+   if you have other `password_providers`. Defaults to true. 
+* `pepper`: Set the value here to a secret random string for extra security. # Uncomment and change to a secret random string for extra security.
+   DO NOT CHANGE THIS AFTER INITIAL SETUP!
+* `policy`: Define and enforce a password policy, such as minimum lengths for passwords, etc. 
+   Each parameter is optional. This is an implementation of MSC2000. Parameters are as follows:
+   * `enabled`: Defaults to false. Set to true to enable.
+   * `minimum_length`: Minimum accepted length for a password. Defaults to 0.
+   * `require_digit`: Whether a password must contain at least one digit.
+      Defaults to false.
+   * `require_symbol`: Whether a password must contain at least one symbol.
+      A symbol is any character that's not a number or a letter. Defaults to false.
+   * `require_lowercase`: Whether a password must contain at least one lowercase letter.
+      Defaults to false.
+   * `require_uppercase`: Whether a password must contain at least one uppercase letter.
+      Defaults to false.
+      
+
+Example configuration:
+```yaml
+password_config:
+   enabled: false
+   localdb_enabled: false
+   pepper: "EVEN_MORE_SECRET"
+
+   policy:
+      enabled: true
+      minimum_length: 15
+      require_digit: true
+      require_symbol: true
+      require_lowercase: true
+      require_uppercase: true
+```
+---
+Config option: `ui_auth`
+
+The amount of time to allow a user-interactive authentication session to be active.
+
+This defaults to 0, meaning the user is queried for their credentials 
+before every action, but this can be overridden to allow a single
+validation to be re-used.  This weakens the protections afforded by
+the user-interactive authentication process, by allowing for multiple
+(and potentially different) operations to use the same validation session.
+
+This is ignored for potentially "dangerous" operations (including
+deactivating an account, modifying an account password, and
+adding a 3PID).
+
+Use the `session_timeout` sub-option here to change the time allowed for credential validation.
+
+Example configuration:
+```yaml
+ui_auth:
+    session_timeout: "15s"
+```
+---
+Config option: `email`
+
+Configuration for sending emails from Synapse.
+
+Server admins can configure custom templates for email content. See
+[here](../../templates.md) for more information.
+
+This setting has the following sub-options:
+* `smtp_host`: The hostname of the outgoing SMTP server to use. Defaults to 'localhost'.
+* `smtp_port`: The port on the mail server for outgoing SMTP. Defaults to 25.
+* `smtp_user` and `smtp_pass`: Username/password for authentication to the SMTP server. By default, no
+   authentication is attempted.
+* `require_transport_security`: Set to true to require TLS transport security for SMTP.
+   By default, Synapse will connect over plain text, and will then switch to
+   TLS via STARTTLS *if the SMTP server supports it*. If this option is set,
+   Synapse will refuse to connect unless the server supports STARTTLS.
+* `enable_tls`: By default, if the server supports TLS, it will be used, and the server
+   must present a certificate that is valid for 'smtp_host'. If this option
+   is set to false, TLS will not be used.
+* `notif_from`: defines the "From" address to use when sending emails.
+    It must be set if email sending is enabled. The placeholder '%(app)s' will be replaced by the application name,
+    which is normally set in `app_name`, but may be overridden by the
+    Matrix client application. Note that the placeholder must be written '%(app)s', including the
+    trailing 's'.
+* `app_name`: `app_name` defines the default value for '%(app)s' in `notif_from` and email
+   subjects. It defaults to 'Matrix'.
+* `enable_notifs`: Set to true to enable sending emails for messages that the user
+   has missed. Disabled by default.
+* `notif_for_new_users`: Set to false to disable automatic subscription to email
+   notifications for new users. Enabled by default.
+* `client_base_url`: Custom URL for client links within the email notifications. By default
+   links will be based on "https://matrix.to". (This setting used to be called `riot_base_url`;
+   the old name is still supported for backwards-compatibility but is now deprecated.)
+* `validation_token_lifetime`: Configures the time that a validation email will expire after sending.
+   Defaults to 1h.
+* `invite_client_location`: The web client location to direct users to during an invite. This is passed
+   to the identity server as the `org.matrix.web_client_location` key. Defaults
+   to unset, giving no guidance to the identity server.
+* `subjects`: Subjects to use when sending emails from Synapse. The placeholder '%(app)s' will
+   be replaced with the value of the `app_name` setting, or by a value dictated by the Matrix client application.
+   In addition, each subject can use the following placeholders: '%(person)s', which will be replaced by the displayname
+   of the user(s) that sent the message(s), e.g. "Alice and Bob", and '%(room)s', which will be replaced by the name of the room the
+   message(s) have been sent to, e.g. "My super room". In addition, emails related to account administration will
+   can use the '%(server_name)s' placeholder, which will be replaced by the value of the
+   `server_name` setting in your Synapse configuration.
+   
+   Here is a list of subjects for notification emails that can be set: 
+     * `message_from_person_in_room`: Subject to use to notify about one message from one or more user(s) in a
+        room which has a name. Defaults to "[%(app)s] You have a message on %(app)s from %(person)s in the %(room)s room..."
+     * `message_from_person`: Subject to use to notify about one message from one or more user(s) in a
+        room which doesn't have a name. Defaults to "[%(app)s] You have a message on %(app)s from %(person)s..."
+     * `messages_from_person`: Subject to use to notify about multiple messages from one or more users in
+        a room which doesn't have a name. Defaults to "[%(app)s] You have messages on %(app)s from %(person)s..."
+     * `messages_in_room`: Subject to use to notify about multiple messages in a room which has a
+        name. Defaults to "[%(app)s] You have messages on %(app)s in the %(room)s room..."
+     * `messages_in_room_and_others`: Subject to use to notify about multiple messages in multiple rooms. 
+        Defaults to "[%(app)s] You have messages on %(app)s in the %(room)s room and others..."
+     * `messages_from_person_and_others`: Subject to use to notify about multiple messages from multiple persons in
+        multiple rooms. This is similar to the setting above except it's used when
+        the room in which the notification was triggered has no name. Defaults to 
+        "[%(app)s] You have messages on %(app)s from %(person)s and others..."
+     * `invite_from_person_to_room`: Subject to use to notify about an invite to a room which has a name. 
+        Defaults to  "[%(app)s] %(person)s has invited you to join the %(room)s room on %(app)s..."
+     * `invite_from_person`: Subject to use to notify about an invite to a room which doesn't have a
+        name. Defaults to "[%(app)s] %(person)s has invited you to chat on %(app)s..."
+     * `password_reset`: Subject to use when sending a password reset email. Defaults to "[%(server_name)s] Password reset"
+     * `email_validation`: Subject to use when sending a verification email to assert an address's
+        ownership. Defaults to "[%(server_name)s] Validate your email"
+
+Example configuration:
+```yaml
+email:
+  smtp_host: mail.server
+  smtp_port: 587
+  smtp_user: "exampleusername"
+  smtp_pass: "examplepassword"
+  require_transport_security: true
+  enable_tls: false
+  notif_from: "Your Friendly %(app)s homeserver <noreply@example.com>"
+  app_name: my_branded_matrix_server
+  enable_notifs: true
+  notif_for_new_users: false
+  client_base_url: "http://localhost/riot"
+  validation_token_lifetime: 15m
+  invite_client_location: https://app.element.io
+
+  subjects:
+    message_from_person_in_room: "[%(app)s] You have a message on %(app)s from %(person)s in the %(room)s room..."
+    message_from_person: "[%(app)s] You have a message on %(app)s from %(person)s..."
+    messages_from_person: "[%(app)s] You have messages on %(app)s from %(person)s..."
+    messages_in_room: "[%(app)s] You have messages on %(app)s in the %(room)s room..."
+    messages_in_room_and_others: "[%(app)s] You have messages on %(app)s in the %(room)s room and others..."
+    messages_from_person_and_others: "[%(app)s] You have messages on %(app)s from %(person)s and others..."
+    invite_from_person_to_room: "[%(app)s] %(person)s has invited you to join the %(room)s room on %(app)s..."
+    invite_from_person: "[%(app)s] %(person)s has invited you to chat on %(app)s..."
+    password_reset: "[%(server_name)s] Password reset"
+    email_validation: "[%(server_name)s] Validate your email"
+```
+---
+## Push ##
+Configuration settings related to push notifications
+
+---
+Config option: `push`
+
+This setting defines options for push notifications. 
+
+This option has a number of sub-options. They are as follows:
+* `include_content`: Clients requesting push notifications can either have the body of
+   the message sent in the notification poke along with other details
+   like the sender, or just the event ID and room ID (`event_id_only`).
+   If clients choose the to have the body sent, this option controls whether the
+   notification request includes the content of the event (other details
+   like the sender are still included). If `event_id_only` is enabled, it
+   has no effect.
+   For modern android devices the notification content will still appear
+   because it is loaded by the app. iPhone, however will send a
+   notification saying only that a message arrived and who it came from.
+   Defaults to true. Set to false to only include the event ID and room ID in push notification payloads.
+* `group_unread_count_by_room: false`: When a push notification is received, an unread count is also sent.
+   This number can either be calculated as the number of unread messages  for the user, or the number of *rooms* the 
+   user has unread messages in. Defaults to true, meaning push clients will see the number of
+   rooms with unread messages in them. Set to false to instead send the number
+   of unread messages.
+
+Example configuration:
+```yaml
+push:
+  include_content: false
+  group_unread_count_by_room: false
+```
+---
+## Rooms ##
+Config options relating to rooms.
+
+---
+Config option: `encryption_enabled_by_default`
+
+Controls whether locally-created rooms should be end-to-end encrypted by
+default.
+
+Possible options are "all", "invite", and "off". They are defined as:
+
+* "all": any locally-created room
+* "invite": any room created with the `private_chat` or `trusted_private_chat`
+   room creation presets
+* "off": this option will take no effect
+
+The default value is "off".
+
+Note that this option will only affect rooms created after it is set. It
+will also not affect rooms created by other servers.
+
+Example configuration:
+```yaml
+encryption_enabled_by_default_for_room_type: invite
+```
+---
+Config option: `enable_group_creation`
+
+Set to true to allow non-server-admin users to create groups on this server
+
+Example configuration:
+```yaml
+enable_group_creation: true
+```
+---
+Config option: `group_creation_prefix`
+
+If enabled/present, non-server admins can only create groups with local parts
+starting with this prefix.
+
+Example configuration:
+```yaml
+group_creation_prefix: "unofficial_"
+```
+---
+Config option: `user_directory`
+
+This setting defines options related to the user directory. 
+
+This option has the following sub-options:
+* `enabled`:  Defines whether users can search the user directory. If false then
+   empty responses are returned to all queries. Defaults to true.
+* `search_all_users`: Defines whether to search all users visible to your HS when searching
+   the user directory. If false, search results will only contain users
+    visible in public rooms and users sharing a room with the requester.
+    Defaults to false.
+    NB. If you set this to true, and the last time the user_directory search
+    indexes were (re)built was before Synapse 1.44, you'll have to
+    rebuild the indexes in order to search through all known users.
+    These indexes are built the first time Synapse starts; admins can
+    manually trigger a rebuild via API following the instructions at
+         https://matrix-org.github.io/synapse/latest/usage/administration/admin_api/background_updates.html#run
+    Set to true to return search results containing all known users, even if that
+    user does not share a room with the requester.
+* `prefer_local_users`: Defines whether to prefer local users in search query results.
+   If set to true, local users are more likely to appear above remote users when searching the 
+   user directory. Defaults to false.
+
+Example configuration:
+```yaml
+user_directory:
+    enabled: false
+    search_all_users: true
+    prefer_local_users: true
+```
+---
+Config option: `user_consent`
+
+For detailed instructions on user consent configuration, see [here](../../consent_tracking.md).
+
+Parts of this section are required if enabling the `consent` resource under
+`listeners`, in particular `template_dir` and `version`. # TODO: link `listeners`
+
+* `template_dir`: gives the location of the templates for the HTML forms.
+  This directory should contain one subdirectory per language (eg, `en`, `fr`),
+  and each language directory should contain the policy document (named as
+  <version>.html) and a success page (success.html).
+
+* `version`: specifies the 'current' version of the policy document. It defines
+   the version to be served by the consent resource if there is no 'v'
+   parameter.
+
+* `server_notice_content`: if enabled, will send a user a "Server Notice"
+   asking them to consent to the privacy policy. The `server_notices` section ##TODO: link
+   must also be configured for this to work. Notices will *not* be sent to
+   guest users unless `send_server_notice_to_guests` is set to true.
+
+* `block_events_error`, if set, will block any attempts to send events
+   until the user consents to the privacy policy. The value of the setting is
+   used as the text of the error.
+
+* `require_at_registration`, if enabled, will add a step to the registration
+   process, similar to how captcha works. Users will be required to accept the
+   policy before their account is created.
+
+* `policy_name` is the display name of the policy users will see when registering
+   for an account. Has no effect unless `require_at_registration` is enabled.
+   Defaults to "Privacy Policy".
+
+Example configuration:
+```yaml
+user_consent:
+  template_dir: res/templates/privacy
+  version: 1.0
+  server_notice_content:
+    msgtype: m.text
+    body: >-
+      To continue using this homeserver you must review and agree to the
+      terms and conditions at %(consent_uri)s
+  send_server_notice_to_guests: true
+  block_events_error: >-
+    To continue using this homeserver you must review and agree to the
+    terms and conditions at %(consent_uri)s
+  require_at_registration: false
+  policy_name: Privacy Policy
+```
+---
+Config option: `stats`
+
+Settings for local room and user statistics collection. See [here](../../room_and_user_statistics.md)
+for more. 
+
+* `enabled`: Set to false to disable room and user statistics. Note that doing
+   so may cause certain features (such as the room directory) not to work
+   correctly. Defaults to true. 
+
+Example configuration:
+```yaml
+stats:  
+  enabled: false
+```
+---
+Config option: `server_notices`
+
+Use this setting to enable a room which can be used to send notices
+from the server to users. It is a special room which users cannot leave; notices
+in the room come from a special "notices" user id.
+
+If you use this setting, you *must* define the `system_mxid_localpart`
+sub-setting, which defines the id of the user which will be used to send the
+notices.
+
+Sub-options for this setting include:
+* `system_mxid_display_name`: set the display name of the "notices" user
+* `system_mxid_avatar_url`: set the avatar for the "notices" user
+* `room_name`: set the room name of the server notices room
+
+Example configuration:
+```yaml
+server_notices:
+  system_mxid_localpart: notices
+  system_mxid_display_name: "Server Notices"
+  system_mxid_avatar_url: "mxc://server.com/oumMVlgDnLYFaPVkExemNVVZ"
+  room_name: "Server Notices"
+```
+---
+Config option: `enable_room_list_search`
+
+Set to false to disable searching the public room list. When disabled
+blocks searching local and remote room lists for local and remote
+users by always returning an empty list for all queries. Defaults to true. 
+
+Example configuration:
+```yaml
+enable_room_list_search: false
+```
+---
+Config option: `alias_creation`
+
+The `alias_creation` option controls who is allowed to create aliases
+on this server.
+
+The format of this option is a list of rules that contain globs that
+match against user_id, room_id and the new alias (fully qualified with
+server name). The action in the first rule that matches is taken,
+which can currently either be "allow" or "deny".
+
+Missing user_id/room_id/alias fields default to "*".
+
+If no rules match the request is denied. An empty list means no one
+can create aliases.
+
+Options for the rules include:
+* `user_id`: Matches against the creator of the alias. Defaults to "*".
+* `alias`: Matches against the alias being created. Defaults to "*".
+* `room_id`: Matches against the room ID the alias is being pointed at. Defaults to "*"
+* `action`: Whether to "allow" or "deny" the request if the rule matches. Defaults to allow. 
+
+Example configuration:
+```yaml
+alias_creation_rules:
+  - user_id: "bad_user"
+    alias: "spammy_alias"
+    room_id: "*"
+    action: deny
+```
+---
+Config options: `room_list_publication_rules`
+
+The `room_list_publication_rules` option controls who can publish and
+which rooms can be published in the public room list.
+
+The format of this option is the same as that for
+`alias_creation_rules`.
+
+If the room has one or more aliases associated with it, only one of
+the aliases needs to match the alias rule. If there are no aliases
+then only rules with `alias: *` match.
+
+If no rules match the request is denied. An empty list means no one
+can publish rooms.
+
+Options for the rules include:
+* `user_id`: Matches against the creator of the alias. Defaults to "*".
+* `alias`: Matches against any current local or canonical aliases associated with the room. Defaults to "*".
+* `room_id`: Matches against the room ID being published. Defaults to "*".
+* `action`: Whether to "allow" or "deny" the request if the rule matches. Defaults to allow. 
+
+Example configuration:
+```yaml
+room_list_publication_rules:
+  - user_id: "*"
+    alias: "*"
+    room_id: "*"
+    action: allow
+```
+---
+## Opentracing ##
+Configuration options related to Opentracing support.
+
+---
+Config option: `opentracing`
+
+These settings enable and configure opentracing, which implements distributed tracing.
+This allows you to observe the causal chains of events across servers
+including requests, key lookups etc., across any server running
+synapse or any other services which support opentracing
+(specifically those implemented with Jaeger).
+
+Sub-options include:
+* `enabled`: whether tracing is enabled. Set to true to enable. Disabled by default.
+* `homeserver_whitelist`: The list of homeservers we wish to send and receive span contexts and span baggage.
+   See [here](../../opentracing.md) for more. 
+   This is a list of regexes which are matched against the `server_name` of the homeserver.
+   By default, it is empty, so no servers are matched.
+* `force_tracing_for_users`: # A list of the matrix IDs of users whose requests will always be traced,
+   even if the tracing system would otherwise drop the traces due to probabilistic sampling.
+    By default, the list is empty.
+* `jaeger_config`: Jaeger can be configured to sample traces at different rates.
+   All configuration options provided by Jaeger can be set here. Jaeger's configuration is 
+   mostly related to trace sampling which is documented [here](https://www.jaegertracing.io/docs/latest/sampling/).
+
+Example configuration:
+```yaml
+opentracing:
+    enabled: true
+    homeserver_whitelist:
+      - ".*"
+    force_tracing_for_users:
+      - "@user1:server_name"
+      - "@user2:server_name"
+
+    jaeger_config:
+      sampler:
+        type: const
+        param: 1
+      logging:
+        false
+```
+---
+## Workers ##
+Configuration options related to workers.
+
+---
+Config option: `send_federation`
+
+Controls sending of outbound federation transactions on the main process.
+Set to false if using a federation sender worker. Defaults to true. 
+
+Example configuration:
+```yaml
+send_federation: false
+```
+---
+Config option: `federation_sender_instances`
+
+It is possible to run multiple federation sender workers, in which case the
+work is balanced across them. Use this setting to list the senders. 
+
+This configuration setting must be shared between all federation sender workers, and if
+changed all federation sender workers must be stopped at the same time and then
+started, to ensure that all instances are running with the same config (otherwise
+events may be dropped). 
+
+Example configuration:
+```yaml
+federation_sender_instances:
+  - federation_sender1
+```
+---
+Config option: `instance_map`
+
+When using workers this should be a map from worker name to the
+HTTP replication listener of the worker, if configured. 
+
+Example configuration:
+```yaml
+instance_map:
+  worker1:
+    host: localhost
+    port: 8034
+```
+---
+Config option: `stream_writers`
+
+Experimental: When using workers you can define which workers should
+handle event persistence and typing notifications. Any worker
+specified here must also be in the `instance_map`.
+
+Example configuration:
+```yaml
+stream_writers:
+  events: worker1
+  typing: worker1
+```
+---
+Config option: `run_background_task_on`
+
+The worker that is used to run background tasks (e.g. cleaning up expired
+data). If not provided this defaults to the main process.
+
+Example configuration:
+```yaml
+run_background_tasks_on: worker1
+```
+---
+Config option: `worker_replication_secret`
+
+A shared secret used by the replication APIs to authenticate HTTP requests
+from workers.
+
+By default this is unused and traffic is not authenticated.
+
+Example configuration:
+```yaml
+worker_replication_secret: "secret_secret"
+```
+Config option: `redis`
+
+Configuration for Redis when using workers. This *must* be enabled when
+using workers (unless using old style direct TCP configuration).
+This setting has the following sub-options:
+* `enabled`: whether to use Redis support. Defaults to false. 
+* `host` and `port`: Optional host and port to use to connect to redis. Defaults to
+   localhost and 6379
+* `password`: Optional password if configured on the Redis instance.
+
+Example configuration:
+```yaml
+redis:
+  enabled: true
+  host: localhost
+  port: 6379
+  password: <secret_password>
+```
+## Background Updates ##
+Configuration settings related to background updates. 
+
+---
+Config option: `background_updates`
+
+Background updates are database updates that are run in the background in batches.
+The duration, minimum batch size, default batch size, whether to sleep between batches and if so, how long to
+sleep can all be configured. This is helpful to speed up or slow down the updates.
+This setting has the following sub-options:
+* `background_update_duration_ms`: How long in milliseconds to run a batch of background updates for. Defaults to 100. 
+   Set a different time to change the default.
+* `sleep_enabled`: Whether to sleep between updates. Defaults to true. Set to false to change the default.
+* `sleep_duration_ms`: If sleeping between updates, how long in milliseconds to sleep for. Defaults to 1000.
+   Set a duration to change the default.
+* `min_batch_size`: Minimum size a batch of background updates can be. Must be greater than 0. Defaults to 1.
+   Set a size to change the default.
+* `default_batch_size`: The batch size to use for the first iteration of a new background update. The default is 100.
+   Set a size to change the default.
+
+Example configuration: 
+```yaml
+background_updates:
+    background_update_duration_ms: 500
+    sleep_enabled: false
+    sleep_duration_ms: 300
+    min_batch_size: 10
+    default_batch_size: 50
+```
\ No newline at end of file
diff --git a/docs/website_files/table-of-contents.js b/docs/website_files/table-of-contents.js
index 0de5960b22..772da97fb9 100644
--- a/docs/website_files/table-of-contents.js
+++ b/docs/website_files/table-of-contents.js
@@ -75,6 +75,20 @@ function setTocEntry() {
  * Populate sidebar on load
  */
 window.addEventListener('load', () => {
+    // Prevent rendering the table of contents of the "print book" page, as it
+    // will end up being rendered into the output (in a broken-looking way)
+
+    // Get the name of the current page (i.e. 'print.html')
+    const pageNameExtension = window.location.pathname.split('/').pop();
+
+    // Split off the extension (as '.../print' is also a valid page name), which
+    // should result in 'print'
+    const pageName = pageNameExtension.split('.')[0];
+    if (pageName === "print") {
+        // Don't render the table of contents on this page
+        return;
+    }
+
     // Only create table of contents if there is more than one header on the page
     if (headers.length <= 1) {
         return;
diff --git a/docs/workers.md b/docs/workers.md
index caef44b614..858411b15e 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -146,12 +146,10 @@ worker_replication_host: 127.0.0.1
 worker_replication_http_port: 9093
 
 worker_listeners:
- - type: http
-   port: 8083
-   resources:
-     - names:
-       - client
-       - federation
+  - type: http
+    port: 8083
+    resources:
+      - names: [client, federation]
 
 worker_log_config: /home/matrix/synapse/config/worker1_log_config.yaml
 ```
@@ -343,9 +341,9 @@ effects of bursts of events from that bridge on events sent by normal users.
 
 #### Stream writers
 
-Additionally, there is *experimental* support for moving writing of specific
-streams (such as events) off of the main process to a particular worker. (This
-is only supported with Redis-based replication.)
+Additionally, the writing of specific streams (such as events) can be moved off
+of the main process to a particular worker.
+(This is only supported with Redis-based replication.)
 
 To enable this, the worker must have a HTTP replication listener configured,
 have a `worker_name` and be listed in the `instance_map` config. The same worker
@@ -422,7 +420,7 @@ the stream writer for the `presence` stream:
 
 #### Background tasks
 
-There is also *experimental* support for moving background tasks to a separate
+There is also support for moving background tasks to a separate
 worker. Background tasks are run periodically or started via replication. Exactly
 which tasks are configured to run depends on your Synapse configuration (e.g. if
 stats is enabled).
diff --git a/poetry.lock b/poetry.lock
index bbe8eba96d..a9f3e61015 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -717,7 +717,7 @@ test = ["appdirs (==1.4.4)", "pytest (>=6)", "pytest-cov (>=2.7)", "pytest-mock
 
 [[package]]
 name = "prometheus-client"
-version = "0.13.1"
+version = "0.14.0"
 description = "Python client for the Prometheus monitoring system."
 category = "main"
 optional = false
@@ -1285,7 +1285,7 @@ urllib3 = ">=1.26.0"
 
 [[package]]
 name = "twisted"
-version = "22.2.0"
+version = "22.4.0"
 description = "An asynchronous networking framework written in Python"
 category = "main"
 optional = false
@@ -1305,19 +1305,20 @@ typing-extensions = ">=3.6.5"
 "zope.interface" = ">=4.4.2"
 
 [package.extras]
-all_non_platform = ["cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
+all_non_platform = ["cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
 conch = ["pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)"]
+conch_nacl = ["pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pynacl"]
 contextvars = ["contextvars (>=2.4,<3)"]
 dev = ["towncrier (>=19.2,<20.0)", "sphinx-rtd-theme (>=0.5,<1.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "pyflakes (>=2.2,<3.0)", "twistedchecker (>=0.7,<1.0)", "coverage (>=6b1,<7)", "python-subunit (>=1.4,<2.0)", "pydoctor (>=21.9.0,<21.10.0)"]
 dev_release = ["towncrier (>=19.2,<20.0)", "sphinx-rtd-theme (>=0.5,<1.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "pydoctor (>=21.9.0,<21.10.0)"]
-http2 = ["h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)"]
-macos_platform = ["pyobjc-core", "pyobjc-framework-cfnetwork", "pyobjc-framework-cocoa", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
-mypy = ["mypy (==0.930)", "mypy-zope (==0.3.4)", "types-setuptools", "types-pyopenssl", "towncrier (>=19.2,<20.0)", "sphinx-rtd-theme (>=0.5,<1.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "pyflakes (>=2.2,<3.0)", "twistedchecker (>=0.7,<1.0)", "coverage (>=6b1,<7)", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "python-subunit (>=1.4,<2.0)", "contextvars (>=2.4,<3)", "pydoctor (>=21.9.0,<21.10.0)"]
-osx_platform = ["pyobjc-core", "pyobjc-framework-cfnetwork", "pyobjc-framework-cocoa", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
+http2 = ["h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)"]
+macos_platform = ["pyobjc-core", "pyobjc-framework-cfnetwork", "pyobjc-framework-cocoa", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
+mypy = ["mypy (==0.930)", "mypy-zope (==0.3.4)", "types-setuptools", "types-pyopenssl", "towncrier (>=19.2,<20.0)", "sphinx-rtd-theme (>=0.5,<1.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "pyflakes (>=2.2,<3.0)", "twistedchecker (>=0.7,<1.0)", "coverage (>=6b1,<7)", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)", "pynacl", "pywin32 (!=226)", "python-subunit (>=1.4,<2.0)", "contextvars (>=2.4,<3)", "pydoctor (>=21.9.0,<21.10.0)"]
+osx_platform = ["pyobjc-core", "pyobjc-framework-cfnetwork", "pyobjc-framework-cocoa", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
 serial = ["pyserial (>=3.0)", "pywin32 (!=226)"]
 test = ["cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)"]
 tls = ["pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)"]
-windows_platform = ["pywin32 (!=226)", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<4.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
+windows_platform = ["pywin32 (!=226)", "cython-test-exception-raiser (>=1.0.2,<2)", "PyHamcrest (>=1.9.0)", "pyopenssl (>=16.0.0)", "service-identity (>=18.1.0)", "idna (>=2.4)", "pyasn1", "cryptography (>=2.6)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "pyserial (>=3.0)", "h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)", "pywin32 (!=226)", "contextvars (>=2.4,<3)"]
 
 [[package]]
 name = "twisted-iocpsupport"
@@ -2225,8 +2226,8 @@ platformdirs = [
     {file = "platformdirs-2.5.1.tar.gz", hash = "sha256:7535e70dfa32e84d4b34996ea99c5e432fa29a708d0f4e394bbcb2a8faa4f16d"},
 ]
 prometheus-client = [
-    {file = "prometheus_client-0.13.1-py3-none-any.whl", hash = "sha256:357a447fd2359b0a1d2e9b311a0c5778c330cfbe186d880ad5a6b39884652316"},
-    {file = "prometheus_client-0.13.1.tar.gz", hash = "sha256:ada41b891b79fca5638bd5cfe149efa86512eaa55987893becd2c6d8d0a5dfc5"},
+    {file = "prometheus_client-0.14.0-py3-none-any.whl", hash = "sha256:f4aba3fdd1735852049f537c1f0ab177159b7ab76f271ecc4d2f45aa2a1d01f2"},
+    {file = "prometheus_client-0.14.0.tar.gz", hash = "sha256:8f7a922dd5455ad524b6ba212ce8eb2b4b05e073f4ec7218287f88b1cac34750"},
 ]
 psycopg2 = [
     {file = "psycopg2-2.9.3-cp310-cp310-win32.whl", hash = "sha256:083707a696e5e1c330af2508d8fab36f9700b26621ccbcb538abe22e15485362"},
@@ -2592,8 +2593,8 @@ twine = [
     {file = "twine-3.8.0.tar.gz", hash = "sha256:8efa52658e0ae770686a13b675569328f1fba9837e5de1867bfe5f46a9aefe19"},
 ]
 twisted = [
-    {file = "Twisted-22.2.0-py3-none-any.whl", hash = "sha256:5c63c149eb6b8fe1e32a0215b1cef96fabdba04f705d8efb9174b1ccf5b49d49"},
-    {file = "Twisted-22.2.0.tar.gz", hash = "sha256:57f32b1f6838facb8c004c89467840367ad38e9e535f8252091345dba500b4f2"},
+    {file = "Twisted-22.4.0-py3-none-any.whl", hash = "sha256:f9f7a91f94932477a9fc3b169d57f54f96c6e74a23d78d9ce54039a7f48928a2"},
+    {file = "Twisted-22.4.0.tar.gz", hash = "sha256:a047990f57dfae1e0bd2b7df2526d4f16dcdc843774dc108b78c52f2a5f13680"},
 ]
 twisted-iocpsupport = [
     {file = "twisted-iocpsupport-1.0.2.tar.gz", hash = "sha256:72068b206ee809c9c596b57b5287259ea41ddb4774d86725b19f35bf56aa32a9"},
diff --git a/scripts-dev/lint.sh b/scripts-dev/lint.sh
index 4698d2d5be..91a704d982 100755
--- a/scripts-dev/lint.sh
+++ b/scripts-dev/lint.sh
@@ -79,8 +79,20 @@ else
   # If we were not asked to lint changed files, and no paths were found as a result,
   # then lint everything!
   if [[ -z ${files+x} ]]; then
-    # Lint all source code files and directories
-      files=( "." )
+      # CI runs each linter on the entire checkout, e.g. `black .`. So don't
+      # rely on this list to *find* lint targets if that misses a file; instead;
+      # use it to exclude files from linters when this can't be done by config.
+      #
+      # To check which files the linters examine, use:
+      #     black --verbose . 2>&1 | \grep -v ignored
+      #     isort --show-files .
+      #     flake8 --verbose .  # This isn't a great option
+      #     mypy has explicit config in mypy.ini; there is also mypy --verbose
+      files=(
+          "synapse" "docker" "tests"
+          "scripts-dev"
+          "contrib" "setup.py" "synmark" "stubs" ".ci"
+      )
   fi
 fi
 
diff --git a/scripts-dev/release.py b/scripts-dev/release.py
index 685fa32b03..518eaf417c 100755
--- a/scripts-dev/release.py
+++ b/scripts-dev/release.py
@@ -69,11 +69,12 @@ def cli():
         # ... wait for assets to build ...
 
         ./scripts-dev/release.py publish
+
         ./scripts-dev/release.py upload
 
         # Optional: generate some nice links for the announcement
 
-        ./scripts-dev/release.py upload
+        ./scripts-dev/release.py announce
 
     If the env var GH_TOKEN (or GITHUB_TOKEN) is set, or passed into the
     `tag`/`publish` command, then a new draft release will be created/published.
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 92907415e6..0172eb60b8 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -179,8 +179,6 @@ class RelationTypes:
     REPLACE: Final = "m.replace"
     REFERENCE: Final = "m.reference"
     THREAD: Final = "m.thread"
-    # TODO Remove this in Synapse >= v1.57.0.
-    UNSTABLE_THREAD: Final = "io.element.thread"
 
 
 class LimitBlockingTypes:
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index 27e97d6f37..4a808e33fe 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -89,9 +89,7 @@ ROOM_EVENT_FILTER_SCHEMA = {
         "org.matrix.not_labels": {"type": "array", "items": {"type": "string"}},
         # MSC3440, filtering by event relations.
         "related_by_senders": {"type": "array", "items": {"type": "string"}},
-        "io.element.relation_senders": {"type": "array", "items": {"type": "string"}},
         "related_by_rel_types": {"type": "array", "items": {"type": "string"}},
-        "io.element.relation_types": {"type": "array", "items": {"type": "string"}},
     },
 }
 
@@ -323,16 +321,6 @@ class Filter:
         self.related_by_senders = self.filter_json.get("related_by_senders", None)
         self.related_by_rel_types = self.filter_json.get("related_by_rel_types", None)
 
-        # Fallback to the unstable prefix if the stable version is not given.
-        if hs.config.experimental.msc3440_enabled:
-            self.related_by_senders = self.related_by_senders or self.filter_json.get(
-                "io.element.relation_senders", None
-            )
-            self.related_by_rel_types = (
-                self.related_by_rel_types
-                or self.filter_json.get("io.element.relation_types", None)
-            )
-
     def filters_all_types(self) -> bool:
         return "*" in self.not_types
 
diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py
index 447476fbfa..979059e723 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -26,9 +26,6 @@ class ExperimentalConfig(Config):
     def read_config(self, config: JsonDict, **kwargs: Any) -> None:
         experimental = config.get("experimental_features") or {}
 
-        # MSC3440 (thread relation)
-        self.msc3440_enabled: bool = experimental.get("msc3440_enabled", False)
-
         # MSC3026 (busy presence state)
         self.msc3026_enabled: bool = experimental.get("msc3026_enabled", False)
 
@@ -77,7 +74,7 @@ class ExperimentalConfig(Config):
         self.msc3720_enabled: bool = experimental.get("msc3720_enabled", False)
 
         # The deprecated groups feature.
-        self.groups_enabled: bool = experimental.get("groups_enabled", True)
+        self.groups_enabled: bool = experimental.get("groups_enabled", False)
 
         # MSC2654: Unread counts
         self.msc2654_enabled: bool = experimental.get("msc2654_enabled", False)
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 415279d269..d771045b52 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -680,14 +680,6 @@ class ServerConfig(Config):
             config.get("use_account_validity_in_account_status") or False
         )
 
-        # This is a temporary option that enables fully using the new
-        # `device_lists_changes_in_room` without the backwards compat code. This
-        # is primarily for testing. If enabled the server should *not* be
-        # downgraded, as it may lead to missing device list updates.
-        self.use_new_device_lists_changes_in_room = (
-            config.get("use_new_device_lists_changes_in_room") or False
-        )
-
         self.rooms_to_exclude_from_sync: List[str] = (
             config.get("exclude_rooms_from_sync") or []
         )
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 918e87ed9c..43c3241fb0 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -39,7 +39,6 @@ from . import EventBase
 
 if TYPE_CHECKING:
     from synapse.handlers.relations import BundledAggregations
-    from synapse.server import HomeServer
 
 
 # Split strings on "." but not "\." This uses a negative lookbehind assertion for '\'
@@ -396,9 +395,6 @@ class EventClientSerializer:
     clients.
     """
 
-    def __init__(self, hs: "HomeServer"):
-        self._msc3440_enabled = hs.config.experimental.msc3440_enabled
-
     def serialize_event(
         self,
         event: Union[JsonDict, EventBase],
@@ -525,8 +521,6 @@ class EventClientSerializer:
                 "current_user_participated": thread.current_user_participated,
             }
             serialized_aggregations[RelationTypes.THREAD] = thread_summary
-            if self._msc3440_enabled:
-                serialized_aggregations[RelationTypes.UNSTABLE_THREAD] = thread_summary
 
         # Include the bundled aggregations in the event.
         if serialized_aggregations:
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 69d833585f..beab1227b8 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -515,7 +515,7 @@ class FederationServer(FederationBase):
         )
 
     async def on_room_state_request(
-        self, origin: str, room_id: str, event_id: Optional[str]
+        self, origin: str, room_id: str, event_id: str
     ) -> Tuple[int, JsonDict]:
         origin_host, _ = parse_server_name(origin)
         await self.check_server_matches_acl(origin_host, room_id)
@@ -530,18 +530,13 @@ class FederationServer(FederationBase):
         # - but that's non-trivial to get right, and anyway somewhat defeats
         # the point of the linearizer.
         async with self._server_linearizer.queue((origin, room_id)):
-            resp: JsonDict = dict(
-                await self._state_resp_cache.wrap(
-                    (room_id, event_id),
-                    self._on_context_state_request_compute,
-                    room_id,
-                    event_id,
-                )
+            resp = await self._state_resp_cache.wrap(
+                (room_id, event_id),
+                self._on_context_state_request_compute,
+                room_id,
+                event_id,
             )
 
-        room_version = await self.store.get_room_version_id(room_id)
-        resp["room_version"] = room_version
-
         return 200, resp
 
     async def on_state_ids_request(
@@ -574,14 +569,11 @@ class FederationServer(FederationBase):
         return {"pdu_ids": state_ids, "auth_chain_ids": list(auth_chain_ids)}
 
     async def _on_context_state_request_compute(
-        self, room_id: str, event_id: Optional[str]
+        self, room_id: str, event_id: str
     ) -> Dict[str, list]:
         pdus: Collection[EventBase]
-        if event_id:
-            event_ids = await self.handler.get_state_ids_for_pdu(room_id, event_id)
-            pdus = await self.store.get_events_as_list(event_ids)
-        else:
-            pdus = (await self.state.get_current_state(room_id)).values()
+        event_ids = await self.handler.get_state_ids_for_pdu(room_id, event_id)
+        pdus = await self.store.get_events_as_list(event_ids)
 
         auth_chain = await self.store.get_auth_chain(
             room_id, [pdu.event_id for pdu in pdus]
@@ -687,8 +679,6 @@ class FederationServer(FederationBase):
         time_now = self._clock.time_msec()
         event_json = event.get_pdu_json(time_now)
         resp = {
-            # TODO Remove the unstable prefix when servers have updated.
-            "org.matrix.msc3083.v2.event": event_json,
             "event": event_json,
             "state": [p.get_pdu_json(time_now) for p in state_events],
             "auth_chain": [p.get_pdu_json(time_now) for p in auth_chain_events],
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 01dc5ca94f..1421050b9a 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -1380,16 +1380,6 @@ class SendJoinParser(ByteParser[SendJoinResponse]):
                 prefix + "auth_chain.item",
                 use_float=True,
             ),
-            # TODO Remove the unstable prefix when servers have updated.
-            #
-            # By re-using the same event dictionary this will cause the parsing of
-            # org.matrix.msc3083.v2.event and event to stomp over each other.
-            # Generally this should be fine.
-            ijson.kvitems_coro(
-                _event_parser(self._response.event_dict),
-                prefix + "org.matrix.msc3083.v2.event",
-                use_float=True,
-            ),
             ijson.kvitems_coro(
                 _event_parser(self._response.event_dict),
                 prefix + "event",
diff --git a/synapse/federation/transport/server/federation.py b/synapse/federation/transport/server/federation.py
index aed3d5069c..6fbc7b5f15 100644
--- a/synapse/federation/transport/server/federation.py
+++ b/synapse/federation/transport/server/federation.py
@@ -160,7 +160,7 @@ class FederationStateV1Servlet(BaseFederationServerServlet):
         return await self.handler.on_room_state_request(
             origin,
             room_id,
-            parse_string_from_args(query, "event_id", None, required=False),
+            parse_string_from_args(query, "event_id", None, required=True),
         )
 
 
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index ffa28b2a30..3c0fc756d4 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -291,12 +291,6 @@ class DeviceHandler(DeviceWorkerHandler):
         # On start up check if there are any updates pending.
         hs.get_reactor().callWhenRunning(self._handle_new_device_update_async)
 
-        # Used to decide if we calculate outbound pokes up front or not. By
-        # default we do to allow safely downgrading Synapse.
-        self.use_new_device_lists_changes_in_room = (
-            hs.config.server.use_new_device_lists_changes_in_room
-        )
-
     def _check_device_name_length(self, name: Optional[str]) -> None:
         """
         Checks whether a device name is longer than the maximum allowed length.
@@ -490,23 +484,9 @@ class DeviceHandler(DeviceWorkerHandler):
 
         room_ids = await self.store.get_rooms_for_user(user_id)
 
-        hosts: Optional[Set[str]] = None
-        if not self.use_new_device_lists_changes_in_room:
-            hosts = set()
-
-            if self.hs.is_mine_id(user_id):
-                for room_id in room_ids:
-                    joined_users = await self.store.get_users_in_room(room_id)
-                    hosts.update(get_domain_from_id(u) for u in joined_users)
-
-                set_tag("target_hosts", hosts)
-
-                hosts.discard(self.server_name)
-
         position = await self.store.add_device_change_to_streams(
             user_id,
             device_ids,
-            hosts=hosts,
             room_ids=room_ids,
         )
 
@@ -528,14 +508,6 @@ class DeviceHandler(DeviceWorkerHandler):
         # We may need to do some processing asynchronously.
         self._handle_new_device_update_async()
 
-        if hosts:
-            logger.info(
-                "Sending device list update notif for %r to: %r", user_id, hosts
-            )
-            for host in hosts:
-                self.federation_sender.send_device_messages(host, immediate=False)
-                log_kv({"message": "sent device update to host", "host": host})
-
     async def notify_user_signature_update(
         self, from_user_id: str, user_ids: List[str]
     ) -> None:
@@ -677,9 +649,13 @@ class DeviceHandler(DeviceWorkerHandler):
                         return
 
                 for user_id, device_id, room_id, stream_id, opentracing_context in rows:
-                    joined_user_ids = await self.store.get_users_in_room(room_id)
-                    hosts = {get_domain_from_id(u) for u in joined_user_ids}
-                    hosts.discard(self.server_name)
+                    hosts = set()
+
+                    # Ignore any users that aren't ours
+                    if self.hs.is_mine_id(user_id):
+                        joined_user_ids = await self.store.get_users_in_room(room_id)
+                        hosts = {get_domain_from_id(u) for u in joined_user_ids}
+                        hosts.discard(self.server_name)
 
                     # Check if we've already sent this update to some hosts
                     if current_stream_id == stream_id:
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index d2ccb5c5d3..e89c4df314 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -16,7 +16,7 @@ import logging
 import random
 from typing import TYPE_CHECKING, Iterable, List, Optional
 
-from synapse.api.constants import EduTypes, EventTypes, Membership
+from synapse.api.constants import EduTypes, EventTypes, Membership, PresenceState
 from synapse.api.errors import AuthError, SynapseError
 from synapse.events import EventBase
 from synapse.events.utils import SerializeEventConfig
@@ -67,7 +67,9 @@ class EventStreamHandler:
         presence_handler = self.hs.get_presence_handler()
 
         context = await presence_handler.user_syncing(
-            auth_user_id, affect_presence=affect_presence
+            auth_user_id,
+            affect_presence=affect_presence,
+            presence_state=PresenceState.ONLINE,
         )
         with context:
             if timeout:
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 78d149905f..1434e99056 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -466,6 +466,8 @@ class FederationHandler:
             )
 
             if ret.partial_state:
+                # TODO(faster_joins): roll this back if we don't manage to start the
+                #   background resync (eg process_remote_join fails)
                 await self.store.store_partial_state_room(room_id, ret.servers_in_room)
 
             max_stream_id = await self._federation_event_handler.process_remote_join(
@@ -478,6 +480,18 @@ class FederationHandler:
                 partial_state=ret.partial_state,
             )
 
+            if ret.partial_state:
+                # Kick off the process of asynchronously fetching the state for this
+                # room.
+                #
+                # TODO(faster_joins): pick this up again on restart
+                run_as_background_process(
+                    desc="sync_partial_state_room",
+                    func=self._sync_partial_state_room,
+                    destination=origin,
+                    room_id=room_id,
+                )
+
             # We wait here until this instance has seen the events come down
             # replication (if we're using replication) as the below uses caches.
             await self._replication.wait_for_stream_position(
@@ -1370,3 +1384,64 @@ class FederationHandler:
         # We fell off the bottom, couldn't get the complexity from anyone. Oh
         # well.
         return None
+
+    async def _sync_partial_state_room(
+        self,
+        destination: str,
+        room_id: str,
+    ) -> None:
+        """Background process to resync the state of a partial-state room
+
+        Args:
+            destination: homeserver to pull the state from
+            room_id: room to be resynced
+        """
+
+        # TODO(faster_joins): do we need to lock to avoid races? What happens if other
+        #   worker processes kick off a resync in parallel? Perhaps we should just elect
+        #   a single worker to do the resync.
+        #
+        # TODO(faster_joins): what happens if we leave the room during a resync? if we
+        #   really leave, that might mean we have difficulty getting the room state over
+        #   federation.
+        #
+        # TODO(faster_joins): try other destinations if the one we have fails
+
+        logger.info("Syncing state for room %s via %s", room_id, destination)
+
+        # we work through the queue in order of increasing stream ordering.
+        while True:
+            batch = await self.store.get_partial_state_events_batch(room_id)
+            if not batch:
+                # all the events are updated, so we can update current state and
+                # clear the lazy-loading flag.
+                logger.info("Updating current state for %s", room_id)
+                assert (
+                    self.storage.persistence is not None
+                ), "TODO(faster_joins): support for workers"
+                await self.storage.persistence.update_current_state(room_id)
+
+                logger.info("Clearing partial-state flag for %s", room_id)
+                success = await self.store.clear_partial_state_room(room_id)
+                if success:
+                    logger.info("State resync complete for %s", room_id)
+
+                    # TODO(faster_joins) update room stats and user directory?
+                    return
+
+                # we raced against more events arriving with partial state. Go round
+                # the loop again. We've already logged a warning, so no need for more.
+                # TODO(faster_joins): there is still a race here, whereby incoming events which raced
+                #   with us will fail to be persisted after the call to `clear_partial_state_room` due to
+                #   having partial state.
+                continue
+
+            events = await self.store.get_events_as_list(
+                batch,
+                redact_behaviour=EventRedactBehaviour.AS_IS,
+                allow_rejected=True,
+            )
+            for event in events:
+                await self._federation_event_handler.update_state_for_partial_state_event(
+                    destination, event
+                )
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 03c1197c99..32bf02818c 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -477,6 +477,45 @@ class FederationEventHandler:
 
             return await self.persist_events_and_notify(room_id, [(event, context)])
 
+    async def update_state_for_partial_state_event(
+        self, destination: str, event: EventBase
+    ) -> None:
+        """Recalculate the state at an event as part of a de-partial-stating process
+
+        Args:
+            destination: server to request full state from
+            event: partial-state event to be de-partial-stated
+        """
+        logger.info("Updating state for %s", event.event_id)
+        with nested_logging_context(suffix=event.event_id):
+            # if we have all the event's prev_events, then we can work out the
+            # state based on their states. Otherwise, we request it from the destination
+            # server.
+            #
+            # This is the same operation as we do when we receive a regular event
+            # over federation.
+            state = await self._resolve_state_at_missing_prevs(destination, event)
+
+            # build a new state group for it if need be
+            context = await self._state_handler.compute_event_context(
+                event,
+                old_state=state,
+            )
+            if context.partial_state:
+                # this can happen if some or all of the event's prev_events still have
+                # partial state - ie, an event has an earlier stream_ordering than one
+                # or more of its prev_events, so we de-partial-state it before its
+                # prev_events.
+                #
+                # TODO(faster_joins): we probably need to be more intelligent, and
+                #    exclude partial-state prev_events from consideration
+                logger.warning(
+                    "%s still has partial state: can't de-partial-state it yet",
+                    event.event_id,
+                )
+                return
+            await self._store.update_state_for_partial_state_event(event, context)
+
     async def backfill(
         self, dest: str, room_id: str, limit: int, extremities: Collection[str]
     ) -> None:
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 7db6905c61..1b092e900e 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -175,17 +175,13 @@ class MessageHandler:
         state_filter = state_filter or StateFilter.all()
 
         if at_token:
-            # FIXME this claims to get the state at a stream position, but
-            # get_recent_events_for_room operates by topo ordering. This therefore
-            # does not reliably give you the state at the given stream position.
-            # (https://github.com/matrix-org/synapse/issues/3305)
-            last_events, _ = await self.store.get_recent_events_for_room(
-                room_id, end_token=at_token.room_key, limit=1
+            last_event = await self.store.get_last_event_in_room_before_stream_ordering(
+                room_id,
+                end_token=at_token.room_key,
             )
 
-            if not last_events:
+            if not last_event:
                 raise NotFoundError("Can't find event for token %s" % (at_token,))
-            last_event = last_events[0]
 
             # check whether the user is in the room at that time to determine
             # whether they should be treated as peeking.
@@ -204,7 +200,7 @@ class MessageHandler:
             visible_events = await filter_events_for_client(
                 self.storage,
                 user_id,
-                last_events,
+                [last_event],
                 filter_send_to_client=False,
                 is_peeking=is_peeking,
             )
@@ -1102,10 +1098,7 @@ class EventCreationHandler:
                 raise SynapseError(400, "Can't send same reaction twice")
 
         # Don't attempt to start a thread if the parent event is a relation.
-        elif (
-            relation_type == RelationTypes.THREAD
-            or relation_type == RelationTypes.UNSTABLE_THREAD
-        ):
+        elif relation_type == RelationTypes.THREAD:
             if await self.store.event_includes_relation(relates_to):
                 raise SynapseError(
                     400, "Cannot start threads from an event with a relation"
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 209a4b0e52..d078162c29 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -151,7 +151,7 @@ class BasePresenceHandler(abc.ABC):
 
     @abc.abstractmethod
     async def user_syncing(
-        self, user_id: str, affect_presence: bool
+        self, user_id: str, affect_presence: bool, presence_state: str
     ) -> ContextManager[None]:
         """Returns a context manager that should surround any stream requests
         from the user.
@@ -165,6 +165,7 @@ class BasePresenceHandler(abc.ABC):
             affect_presence: If false this function will be a no-op.
                 Useful for streams that are not associated with an actual
                 client that is being used by a user.
+            presence_state: The presence state indicated in the sync request
         """
 
     @abc.abstractmethod
@@ -228,6 +229,11 @@ class BasePresenceHandler(abc.ABC):
 
         return states
 
+    async def current_state_for_user(self, user_id: str) -> UserPresenceState:
+        """Get the current presence state for a user."""
+        res = await self.current_state_for_users([user_id])
+        return res[user_id]
+
     @abc.abstractmethod
     async def set_state(
         self,
@@ -461,7 +467,7 @@ class WorkerPresenceHandler(BasePresenceHandler):
                 self.send_user_sync(user_id, False, last_sync_ms)
 
     async def user_syncing(
-        self, user_id: str, affect_presence: bool
+        self, user_id: str, affect_presence: bool, presence_state: str
     ) -> ContextManager[None]:
         """Record that a user is syncing.
 
@@ -471,6 +477,17 @@ class WorkerPresenceHandler(BasePresenceHandler):
         if not affect_presence or not self._presence_enabled:
             return _NullContextManager()
 
+        prev_state = await self.current_state_for_user(user_id)
+        if prev_state != PresenceState.BUSY:
+            # We set state here but pass ignore_status_msg = True as we don't want to
+            # cause the status message to be cleared.
+            # Note that this causes last_active_ts to be incremented which is not
+            # what the spec wants: see comment in the BasePresenceHandler version
+            # of this function.
+            await self.set_state(
+                UserID.from_string(user_id), {"presence": presence_state}, True
+            )
+
         curr_sync = self._user_to_num_current_syncs.get(user_id, 0)
         self._user_to_num_current_syncs[user_id] = curr_sync + 1
 
@@ -942,7 +959,10 @@ class PresenceHandler(BasePresenceHandler):
         await self._update_states([prev_state.copy_and_replace(**new_fields)])
 
     async def user_syncing(
-        self, user_id: str, affect_presence: bool = True
+        self,
+        user_id: str,
+        affect_presence: bool = True,
+        presence_state: str = PresenceState.ONLINE,
     ) -> ContextManager[None]:
         """Returns a context manager that should surround any stream requests
         from the user.
@@ -956,6 +976,7 @@ class PresenceHandler(BasePresenceHandler):
             affect_presence: If false this function will be a no-op.
                 Useful for streams that are not associated with an actual
                 client that is being used by a user.
+            presence_state: The presence state indicated in the sync request
         """
         # Override if it should affect the user's presence, if presence is
         # disabled.
@@ -967,9 +988,25 @@ class PresenceHandler(BasePresenceHandler):
             self.user_to_num_current_syncs[user_id] = curr_sync + 1
 
             prev_state = await self.current_state_for_user(user_id)
+
+            # If they're busy then they don't stop being busy just by syncing,
+            # so just update the last sync time.
+            if prev_state.state != PresenceState.BUSY:
+                # XXX: We set_state separately here and just update the last_active_ts above
+                # This keeps the logic as similar as possible between the worker and single
+                # process modes. Using set_state will actually cause last_active_ts to be
+                # updated always, which is not what the spec calls for, but synapse has done
+                # this for... forever, I think.
+                await self.set_state(
+                    UserID.from_string(user_id), {"presence": presence_state}, True
+                )
+                # Retrieve the new state for the logic below. This should come from the
+                # in-memory cache.
+                prev_state = await self.current_state_for_user(user_id)
+
+            # To keep the single process behaviour consistent with worker mode, run the
+            # same logic as `update_external_syncs_row`, even though it looks weird.
             if prev_state.state == PresenceState.OFFLINE:
-                # If they're currently offline then bring them online, otherwise
-                # just update the last sync times.
                 await self._update_states(
                     [
                         prev_state.copy_and_replace(
@@ -979,6 +1016,10 @@ class PresenceHandler(BasePresenceHandler):
                         )
                     ]
                 )
+            # otherwise, set the new presence state & update the last sync time,
+            # but don't update last_active_ts as this isn't an indication that
+            # they've been active (even though it's probably been updated by
+            # set_state above)
             else:
                 await self._update_states(
                     [
@@ -1086,11 +1127,6 @@ class PresenceHandler(BasePresenceHandler):
             )
             self.external_process_last_updated_ms.pop(process_id, None)
 
-    async def current_state_for_user(self, user_id: str) -> UserPresenceState:
-        """Get the current presence state for a user."""
-        res = await self.current_state_for_users([user_id])
-        return res[user_id]
-
     async def _persist_and_notify(self, states: List[UserPresenceState]) -> None:
         """Persist states in the database, poke the notifier and send to
         interested remote servers
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 6c8b17c420..5125126a80 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -661,16 +661,15 @@ class SyncHandler:
             stream_position: point at which to get state
             state_filter: The state filter used to fetch state from the database.
         """
-        # FIXME this claims to get the state at a stream position, but
-        # get_recent_events_for_room operates by topo ordering. This therefore
-        # does not reliably give you the state at the given stream position.
-        # (https://github.com/matrix-org/synapse/issues/3305)
-        last_events, _ = await self.store.get_recent_events_for_room(
-            room_id, end_token=stream_position.room_key, limit=1
+        # FIXME: This gets the state at the latest event before the stream ordering,
+        # which might not be the same as the "current state" of the room at the time
+        # of the stream token if there were multiple forward extremities at the time.
+        last_event = await self.store.get_last_event_in_room_before_stream_ordering(
+            room_id,
+            end_token=stream_position.room_key,
         )
 
-        if last_events:
-            last_event = last_events[-1]
+        if last_event:
             state = await self.get_state_after_event(
                 last_event, state_filter=state_filter or StateFilter.all()
             )
diff --git a/synapse/rest/client/login.py b/synapse/rest/client/login.py
index c9d44c5964..4a4dbe75de 100644
--- a/synapse/rest/client/login.py
+++ b/synapse/rest/client/login.py
@@ -342,6 +342,15 @@ class LoginRestServlet(RestServlet):
             user_id = canonical_uid
 
         device_id = login_submission.get("device_id")
+
+        # If device_id is present, check that device_id is not longer than a reasonable 512 characters
+        if device_id and len(device_id) > 512:
+            raise LoginError(
+                400,
+                "device_id cannot be longer than 512 characters.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
         initial_display_name = login_submission.get("initial_device_display_name")
         (
             device_id,
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index 2e25e8638b..e8772f86e7 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -180,13 +180,10 @@ class SyncRestServlet(RestServlet):
 
         affect_presence = set_presence != PresenceState.OFFLINE
 
-        if affect_presence:
-            await self.presence_handler.set_state(
-                user, {"presence": set_presence}, True
-            )
-
         context = await self.presence_handler.user_syncing(
-            user.to_string(), affect_presence=affect_presence
+            user.to_string(),
+            affect_presence=affect_presence,
+            presence_state=set_presence,
         )
         with context:
             sync_result = await self.sync_handler.wait_for_sync_for_user(
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 9a65aa4843..7b29026381 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -86,7 +86,7 @@ class VersionsRestServlet(RestServlet):
                     # Implements additional endpoints as described in MSC2432
                     "org.matrix.msc2432": True,
                     # Implements additional endpoints as described in MSC2666
-                    "uk.half-shot.msc2666": True,
+                    "uk.half-shot.msc2666.mutual_rooms": True,
                     # Whether new rooms will be set to encrypted or not (based on presets).
                     "io.element.e2ee_forced.public": self.e2ee_forced_public,
                     "io.element.e2ee_forced.private": self.e2ee_forced_private,
@@ -100,7 +100,6 @@ class VersionsRestServlet(RestServlet):
                     # Adds support for jump to date endpoints (/timestamp_to_event) as per MSC3030
                     "org.matrix.msc3030": self.config.experimental.msc3030_enabled,
                     # Adds support for thread relations, per MSC3440.
-                    "org.matrix.msc3440": self.config.experimental.msc3440_enabled,
                     "org.matrix.msc3440.stable": True,  # TODO: remove when "v1.3" is added above
                 },
             },
diff --git a/synapse/server.py b/synapse/server.py
index 380369db92..37c72bd83a 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -758,7 +758,7 @@ class HomeServer(metaclass=abc.ABCMeta):
 
     @cache_in_self
     def get_event_client_serializer(self) -> EventClientSerializer:
-        return EventClientSerializer(self)
+        return EventClientSerializer()
 
     @cache_in_self
     def get_password_policy_handler(self) -> PasswordPolicyHandler:
diff --git a/synapse/storage/databases/main/devices.py b/synapse/storage/databases/main/devices.py
index dc8009b23d..318e4df376 100644
--- a/synapse/storage/databases/main/devices.py
+++ b/synapse/storage/databases/main/devices.py
@@ -1582,7 +1582,6 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         self,
         user_id: str,
         device_ids: Collection[str],
-        hosts: Optional[Collection[str]],
         room_ids: Collection[str],
     ) -> Optional[int]:
         """Persist that a user's devices have been updated, and which hosts
@@ -1592,9 +1591,6 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             user_id: The ID of the user whose device changed.
             device_ids: The IDs of any changed devices. If empty, this function will
                 return None.
-            hosts: The remote destinations that should be notified of the change. If
-                None then the set of hosts have *not* been calculated, and will be
-                calculated later by a background task.
             room_ids: The rooms that the user is in
 
         Returns:
@@ -1606,14 +1602,12 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
 
         context = get_active_span_text_map()
 
-        def add_device_changes_txn(
-            txn, stream_ids_for_device_change, stream_ids_for_outbound_pokes
-        ):
+        def add_device_changes_txn(txn, stream_ids):
             self._add_device_change_to_stream_txn(
                 txn,
                 user_id,
                 device_ids,
-                stream_ids_for_device_change,
+                stream_ids,
             )
 
             self._add_device_outbound_room_poke_txn(
@@ -1621,43 +1615,17 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                 user_id,
                 device_ids,
                 room_ids,
-                stream_ids_for_device_change,
-                context,
-                hosts_have_been_calculated=hosts is not None,
-            )
-
-            # If the set of hosts to send to has not been calculated yet (and so
-            # `hosts` is None) or there are no `hosts` to send to, then skip
-            # trying to persist them to the DB.
-            if not hosts:
-                return
-
-            self._add_device_outbound_poke_to_stream_txn(
-                txn,
-                user_id,
-                device_ids,
-                hosts,
-                stream_ids_for_outbound_pokes,
+                stream_ids,
                 context,
             )
 
-        # `device_lists_stream` wants a stream ID per device update.
-        num_stream_ids = len(device_ids)
-
-        if hosts:
-            # `device_lists_outbound_pokes` wants a different stream ID for
-            # each row, which is a row per host per device update.
-            num_stream_ids += len(hosts) * len(device_ids)
-
-        async with self._device_list_id_gen.get_next_mult(num_stream_ids) as stream_ids:
-            stream_ids_for_device_change = stream_ids[: len(device_ids)]
-            stream_ids_for_outbound_pokes = stream_ids[len(device_ids) :]
-
+        async with self._device_list_id_gen.get_next_mult(
+            len(device_ids)
+        ) as stream_ids:
             await self.db_pool.runInteraction(
                 "add_device_change_to_stream",
                 add_device_changes_txn,
-                stream_ids_for_device_change,
-                stream_ids_for_outbound_pokes,
+                stream_ids,
             )
 
         return stream_ids[-1]
@@ -1735,7 +1703,9 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                     next(stream_id_iterator),
                     user_id,
                     device_id,
-                    False,
+                    not self.hs.is_mine_id(
+                        user_id
+                    ),  # We only need to send out update for *our* users
                     now,
                     encoded_context if whitelisted_homeserver(destination) else "{}",
                 )
@@ -1752,19 +1722,8 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         room_ids: Collection[str],
         stream_ids: List[str],
         context: Dict[str, str],
-        hosts_have_been_calculated: bool,
     ) -> None:
-        """Record the user in the room has updated their device.
-
-        Args:
-            hosts_have_been_calculated: True if `device_lists_outbound_pokes`
-                has been updated already with the updates.
-        """
-
-        # We only need to convert to outbound pokes if they are our user.
-        converted_to_destinations = (
-            hosts_have_been_calculated or not self.hs.is_mine_id(user_id)
-        )
+        """Record the user in the room has updated their device."""
 
         encoded_context = json_encoder.encode(context)
 
@@ -1789,7 +1748,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                     device_id,
                     room_id,
                     stream_id,
-                    converted_to_destinations,
+                    False,
                     encoded_context,
                 )
                 for room_id in room_ids
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 3fcd5f5b99..2a1e567ce0 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -963,6 +963,21 @@ class PersistEventsStore:
                 values=to_insert,
             )
 
+    async def update_current_state(
+        self,
+        room_id: str,
+        state_delta: DeltaState,
+        stream_id: int,
+    ) -> None:
+        """Update the current state stored in the datatabase for the given room"""
+
+        await self.db_pool.runInteraction(
+            "update_current_state",
+            self._update_current_state_txn,
+            state_delta_by_room={room_id: state_delta},
+            stream_id=stream_id,
+        )
+
     def _update_current_state_txn(
         self,
         txn: LoggingTransaction,
@@ -1819,10 +1834,7 @@ class PersistEventsStore:
         if rel_type == RelationTypes.REPLACE:
             txn.call_after(self.store.get_applicable_edit.invalidate, (parent_id,))
 
-        if (
-            rel_type == RelationTypes.THREAD
-            or rel_type == RelationTypes.UNSTABLE_THREAD
-        ):
+        if rel_type == RelationTypes.THREAD:
             txn.call_after(self.store.get_thread_summary.invalidate, (parent_id,))
             # It should be safe to only invalidate the cache if the user has not
             # previously participated in the thread, but that's difficult (and
diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py
index a60e3f4fdd..5288cdba03 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -1979,3 +1979,27 @@ class EventsWorkerStore(SQLBaseStore):
             desc="is_partial_state_event",
         )
         return result is not None
+
+    async def get_partial_state_events_batch(self, room_id: str) -> List[str]:
+        """Get a list of events in the given room that have partial state"""
+        return await self.db_pool.runInteraction(
+            "get_partial_state_events_batch",
+            self._get_partial_state_events_batch_txn,
+            room_id,
+        )
+
+    @staticmethod
+    def _get_partial_state_events_batch_txn(
+        txn: LoggingTransaction, room_id: str
+    ) -> List[str]:
+        txn.execute(
+            """
+            SELECT event_id FROM partial_state_events AS pse
+                JOIN events USING (event_id)
+            WHERE pse.room_id = ?
+            ORDER BY events.stream_ordering
+            LIMIT 100
+            """,
+            (room_id,),
+        )
+        return [row[0] for row in txn]
diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py
index 407158ceee..a5c31f6787 100644
--- a/synapse/storage/databases/main/relations.py
+++ b/synapse/storage/databases/main/relations.py
@@ -14,7 +14,6 @@
 
 import logging
 from typing import (
-    TYPE_CHECKING,
     Collection,
     Dict,
     FrozenSet,
@@ -32,20 +31,12 @@ import attr
 from synapse.api.constants import RelationTypes
 from synapse.events import EventBase
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import (
-    DatabasePool,
-    LoggingDatabaseConnection,
-    LoggingTransaction,
-    make_in_list_sql_clause,
-)
+from synapse.storage.database import LoggingTransaction, make_in_list_sql_clause
 from synapse.storage.databases.main.stream import generate_pagination_where_clause
 from synapse.storage.engines import PostgresEngine
 from synapse.types import JsonDict, RoomStreamToken, StreamToken
 from synapse.util.caches.descriptors import cached, cachedList
 
-if TYPE_CHECKING:
-    from synapse.server import HomeServer
-
 logger = logging.getLogger(__name__)
 
 
@@ -63,16 +54,6 @@ class _RelatedEvent:
 
 
 class RelationsWorkerStore(SQLBaseStore):
-    def __init__(
-        self,
-        database: DatabasePool,
-        db_conn: LoggingDatabaseConnection,
-        hs: "HomeServer",
-    ):
-        super().__init__(database, db_conn, hs)
-
-        self._msc3440_enabled = hs.config.experimental.msc3440_enabled
-
     @cached(uncached_args=("event",), tree=True)
     async def get_relations_for_event(
         self,
@@ -497,7 +478,7 @@ class RelationsWorkerStore(SQLBaseStore):
                         AND parent.room_id = child.room_id
                     WHERE
                         %s
-                        AND %s
+                        AND relation_type = ?
                     ORDER BY parent.event_id, child.topological_ordering DESC, child.stream_ordering DESC
                 """
             else:
@@ -512,22 +493,16 @@ class RelationsWorkerStore(SQLBaseStore):
                         AND parent.room_id = child.room_id
                     WHERE
                         %s
-                        AND %s
+                        AND relation_type = ?
                     ORDER BY child.topological_ordering DESC, child.stream_ordering DESC
                 """
 
             clause, args = make_in_list_sql_clause(
                 txn.database_engine, "relates_to_id", event_ids
             )
+            args.append(RelationTypes.THREAD)
 
-            if self._msc3440_enabled:
-                relations_clause = "(relation_type = ? OR relation_type = ?)"
-                args.extend((RelationTypes.THREAD, RelationTypes.UNSTABLE_THREAD))
-            else:
-                relations_clause = "relation_type = ?"
-                args.append(RelationTypes.THREAD)
-
-            txn.execute(sql % (clause, relations_clause), args)
+            txn.execute(sql % (clause,), args)
             latest_event_ids = {}
             for parent_event_id, child_event_id in txn:
                 # Only consider the latest threaded reply (by topological ordering).
@@ -547,7 +522,7 @@ class RelationsWorkerStore(SQLBaseStore):
                     AND parent.room_id = child.room_id
                 WHERE
                     %s
-                    AND %s
+                    AND relation_type = ?
                 GROUP BY parent.event_id
             """
 
@@ -556,15 +531,9 @@ class RelationsWorkerStore(SQLBaseStore):
             clause, args = make_in_list_sql_clause(
                 txn.database_engine, "relates_to_id", latest_event_ids.keys()
             )
+            args.append(RelationTypes.THREAD)
 
-            if self._msc3440_enabled:
-                relations_clause = "(relation_type = ? OR relation_type = ?)"
-                args.extend((RelationTypes.THREAD, RelationTypes.UNSTABLE_THREAD))
-            else:
-                relations_clause = "relation_type = ?"
-                args.append(RelationTypes.THREAD)
-
-            txn.execute(sql % (clause, relations_clause), args)
+            txn.execute(sql % (clause,), args)
             counts = dict(cast(List[Tuple[str, int]], txn.fetchall()))
 
             return counts, latest_event_ids
@@ -622,7 +591,7 @@ class RelationsWorkerStore(SQLBaseStore):
                 parent.event_id = relates_to_id
                 AND parent.room_id = child.room_id
             WHERE
-                %s
+                relation_type = ?
                 AND %s
                 AND %s
             GROUP BY parent.event_id, child.sender
@@ -638,16 +607,9 @@ class RelationsWorkerStore(SQLBaseStore):
                 txn.database_engine, "relates_to_id", event_ids
             )
 
-            if self._msc3440_enabled:
-                relations_clause = "(relation_type = ? OR relation_type = ?)"
-                relations_args = [RelationTypes.THREAD, RelationTypes.UNSTABLE_THREAD]
-            else:
-                relations_clause = "relation_type = ?"
-                relations_args = [RelationTypes.THREAD]
-
             txn.execute(
-                sql % (users_sql, events_clause, relations_clause),
-                users_args + events_args + relations_args,
+                sql % (users_sql, events_clause),
+                [RelationTypes.THREAD] + users_args + events_args,
             )
             return {(row[0], row[1]): row[2] for row in txn}
 
@@ -677,7 +639,7 @@ class RelationsWorkerStore(SQLBaseStore):
             user participated in that event's thread, otherwise false.
         """
 
-        def _get_thread_summary_txn(txn: LoggingTransaction) -> Set[str]:
+        def _get_threads_participated_txn(txn: LoggingTransaction) -> Set[str]:
             # Fetch whether the requester has participated or not.
             sql = """
                 SELECT DISTINCT relates_to_id
@@ -688,28 +650,20 @@ class RelationsWorkerStore(SQLBaseStore):
                     AND parent.room_id = child.room_id
                 WHERE
                     %s
-                    AND %s
+                    AND relation_type = ?
                     AND child.sender = ?
             """
 
             clause, args = make_in_list_sql_clause(
                 txn.database_engine, "relates_to_id", event_ids
             )
+            args.extend([RelationTypes.THREAD, user_id])
 
-            if self._msc3440_enabled:
-                relations_clause = "(relation_type = ? OR relation_type = ?)"
-                args.extend((RelationTypes.THREAD, RelationTypes.UNSTABLE_THREAD))
-            else:
-                relations_clause = "relation_type = ?"
-                args.append(RelationTypes.THREAD)
-
-            args.append(user_id)
-
-            txn.execute(sql % (clause, relations_clause), args)
+            txn.execute(sql % (clause,), args)
             return {row[0] for row in txn.fetchall()}
 
         participated_threads = await self.db_pool.runInteraction(
-            "get_thread_summary", _get_thread_summary_txn
+            "get_threads_participated", _get_threads_participated_txn
         )
 
         return {event_id: event_id in participated_threads for event_id in event_ids}
diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index 18b1acd9e1..87e9482c60 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -1077,6 +1077,37 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
             get_rooms_for_retention_period_in_range_txn,
         )
 
+    async def clear_partial_state_room(self, room_id: str) -> bool:
+        # this can race with incoming events, so we watch out for FK errors.
+        # TODO(faster_joins): this still doesn't completely fix the race, since the persist process
+        #   is not atomic. I fear we need an application-level lock.
+        try:
+            await self.db_pool.runInteraction(
+                "clear_partial_state_room", self._clear_partial_state_room_txn, room_id
+            )
+            return True
+        except self.db_pool.engine.module.DatabaseError as e:
+            # TODO(faster_joins): how do we distinguish between FK errors and other errors?
+            logger.warning(
+                "Exception while clearing lazy partial-state-room %s, retrying: %s",
+                room_id,
+                e,
+            )
+            return False
+
+    @staticmethod
+    def _clear_partial_state_room_txn(txn: LoggingTransaction, room_id: str) -> None:
+        DatabasePool.simple_delete_txn(
+            txn,
+            table="partial_state_rooms_servers",
+            keyvalues={"room_id": room_id},
+        )
+        DatabasePool.simple_delete_one_txn(
+            txn,
+            table="partial_state_rooms",
+            keyvalues={"room_id": room_id},
+        )
+
 
 class _BackgroundUpdates:
     REMOVE_TOMESTONED_ROOMS_BG_UPDATE = "remove_tombstoned_rooms_from_directory"
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index ecdc1fdc4c..7a1b013fa3 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -21,6 +21,7 @@ from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import NotFoundError, UnsupportedRoomVersionError
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
 from synapse.events import EventBase
+from synapse.events.snapshot import EventContext
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import (
     DatabasePool,
@@ -129,7 +130,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         )
 
         if room_version is None:
-            raise NotFoundError("Could not room_version for %s" % (room_id,))
+            raise NotFoundError("Could not find room_version for %s" % (room_id,))
 
         return room_version
 
@@ -354,6 +355,53 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         return {row["state_group"] for row in rows}
 
+    async def update_state_for_partial_state_event(
+        self,
+        event: EventBase,
+        context: EventContext,
+    ) -> None:
+        """Update the state group for a partial state event"""
+        await self.db_pool.runInteraction(
+            "update_state_for_partial_state_event",
+            self._update_state_for_partial_state_event_txn,
+            event,
+            context,
+        )
+
+    def _update_state_for_partial_state_event_txn(
+        self,
+        txn,
+        event: EventBase,
+        context: EventContext,
+    ):
+        # we shouldn't have any outliers here
+        assert not event.internal_metadata.is_outlier()
+
+        # anything that was rejected should have the same state as its
+        # predecessor.
+        if context.rejected:
+            assert context.state_group == context.state_group_before_event
+
+        self.db_pool.simple_update_txn(
+            txn,
+            table="event_to_state_groups",
+            keyvalues={"event_id": event.event_id},
+            updatevalues={"state_group": context.state_group},
+        )
+
+        self.db_pool.simple_delete_one_txn(
+            txn,
+            table="partial_state_events",
+            keyvalues={"event_id": event.event_id},
+        )
+
+        # TODO(faster_joins): need to do something about workers here
+        txn.call_after(
+            self._get_state_group_for_event.prefill,
+            (event.event_id,),
+            context.state_group,
+        )
+
 
 class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
 
diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py
index 6d45a8a9f6..793e906630 100644
--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -758,6 +758,32 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             "get_room_event_before_stream_ordering", _f
         )
 
+    async def get_last_event_in_room_before_stream_ordering(
+        self,
+        room_id: str,
+        end_token: RoomStreamToken,
+    ) -> Optional[EventBase]:
+        """Returns the last event in a room at or before a stream ordering
+
+        Args:
+            room_id
+            end_token: The token used to stream from
+
+        Returns:
+            The most recent event.
+        """
+
+        last_row = await self.get_room_event_before_stream_ordering(
+            room_id=room_id,
+            stream_ordering=end_token.stream,
+        )
+        if last_row:
+            _, _, event_id = last_row
+            event = await self.get_event(event_id, get_prev_content=True)
+            return event
+
+        return None
+
     async def get_current_room_stream_token_for_room_id(
         self, room_id: Optional[str] = None
     ) -> RoomStreamToken:
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index b402922817..e496ba7bed 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -376,6 +376,62 @@ class EventsPersistenceStorage:
         pos = PersistedEventPosition(self._instance_name, event_stream_id)
         return event, pos, self.main_store.get_room_max_token()
 
+    async def update_current_state(self, room_id: str) -> None:
+        """Recalculate the current state for a room, and persist it"""
+        state = await self._calculate_current_state(room_id)
+        delta = await self._calculate_state_delta(room_id, state)
+
+        # TODO(faster_joins): get a real stream ordering, to make this work correctly
+        #    across workers.
+        #
+        # TODO(faster_joins): this can race against event persistence, in which case we
+        #    will end up with incorrect state. Perhaps we should make this a job we
+        #    farm out to the event persister, somehow.
+        stream_id = self.main_store.get_room_max_stream_ordering()
+        await self.persist_events_store.update_current_state(room_id, delta, stream_id)
+
+    async def _calculate_current_state(self, room_id: str) -> StateMap[str]:
+        """Calculate the current state of a room, based on the forward extremities
+
+        Args:
+            room_id: room for which to calculate current state
+
+        Returns:
+            map from (type, state_key) to event id for the  current state in the room
+        """
+        latest_event_ids = await self.main_store.get_latest_event_ids_in_room(room_id)
+        state_groups = set(
+            (
+                await self.main_store._get_state_group_for_events(latest_event_ids)
+            ).values()
+        )
+
+        state_maps_by_state_group = await self.state_store._get_state_for_groups(
+            state_groups
+        )
+
+        if len(state_groups) == 1:
+            # If there is only one state group, then we know what the current
+            # state is.
+            return state_maps_by_state_group[state_groups.pop()]
+
+        # Ok, we need to defer to the state handler to resolve our state sets.
+        logger.debug("calling resolve_state_groups from preserve_events")
+
+        # Avoid a circular import.
+        from synapse.state import StateResolutionStore
+
+        room_version = await self.main_store.get_room_version_id(room_id)
+        res = await self._state_resolution_handler.resolve_state_groups(
+            room_id,
+            room_version,
+            state_maps_by_state_group,
+            event_map=None,
+            state_res_store=StateResolutionStore(self.main_store),
+        )
+
+        return res.state
+
     async def _persist_event_batch(
         self,
         events_and_contexts: List[Tuple[EventBase, EventContext]],
diff --git a/synapse/storage/schema/__init__.py b/synapse/storage/schema/__init__.py
index 151f2aa9bb..871d4ace12 100644
--- a/synapse/storage/schema/__init__.py
+++ b/synapse/storage/schema/__init__.py
@@ -66,9 +66,9 @@ Changes in SCHEMA_VERSION = 69:
 
 
 SCHEMA_COMPAT_VERSION = (
-    # we now have `state_key` columns in both `events` and `state_events`, so
-    # now incompatible with synapses wth SCHEMA_VERSION < 66.
-    66
+    # We now assume that `device_lists_changes_in_room` has been filled out for
+    # recent device_list_updates.
+    69
 )
 """Limit on how far the synapse codebase can be rolled back without breaking db compat
 
diff --git a/sytest-blacklist b/sytest-blacklist
index 57e603a4a6..d5fa36cec7 100644
--- a/sytest-blacklist
+++ b/sytest-blacklist
@@ -21,10 +21,6 @@ Newly created users see their own presence in /initialSync (SYT-34)
 # Blacklisted due to https://github.com/matrix-org/synapse/issues/1396
 Should reject keys claiming to belong to a different user
 
-# Blacklisted due to https://github.com/matrix-org/matrix-doc/pull/2314 removing
-# this requirement from the spec
-Inbound federation of state requires event_id as a mandatory paramater
-
 # Blacklisted until MSC2753 is implemented
 Local users can peek into world_readable rooms by room ID
 We can't peek into rooms with shared history_visibility
diff --git a/tests/api/test_filtering.py b/tests/api/test_filtering.py
index 8c3354ce3c..985d6e397d 100644
--- a/tests/api/test_filtering.py
+++ b/tests/api/test_filtering.py
@@ -481,9 +481,7 @@ class FilteringTestCase(unittest.HomeserverTestCase):
         # events). This is a bit cheeky, but tests the logic of _check_event_relations.
 
         # Filter for a particular sender.
-        definition = {
-            "io.element.relation_senders": ["@foo:bar"],
-        }
+        definition = {"related_by_senders": ["@foo:bar"]}
 
         async def events_have_relations(*args, **kwargs):
             return ["$with_relation"]
diff --git a/tests/federation/test_federation_sender.py b/tests/federation/test_federation_sender.py
index a6e91956af..91f982518e 100644
--- a/tests/federation/test_federation_sender.py
+++ b/tests/federation/test_federation_sender.py
@@ -14,7 +14,6 @@
 from typing import Optional
 from unittest.mock import Mock
 
-from parameterized import parameterized_class
 from signedjson import key, sign
 from signedjson.types import BaseKey, SigningKey
 
@@ -155,12 +154,6 @@ class FederationSenderReceiptsTestCases(HomeserverTestCase):
         )
 
 
-@parameterized_class(
-    [
-        {"enable_room_poke_code_path": False},
-        {"enable_room_poke_code_path": True},
-    ]
-)
 class FederationSenderDevicesTestCases(HomeserverTestCase):
     servlets = [
         admin.register_servlets,
@@ -169,13 +162,14 @@ class FederationSenderDevicesTestCases(HomeserverTestCase):
 
     def make_homeserver(self, reactor, clock):
         return self.setup_test_homeserver(
-            federation_transport_client=Mock(spec=["send_transaction"]),
+            federation_transport_client=Mock(
+                spec=["send_transaction", "query_user_devices"]
+            ),
         )
 
     def default_config(self):
         c = super().default_config()
         c["send_federation"] = True
-        c["use_new_device_lists_changes_in_room"] = self.enable_room_poke_code_path
         return c
 
     def prepare(self, reactor, clock, hs):
@@ -226,6 +220,45 @@ class FederationSenderDevicesTestCases(HomeserverTestCase):
         self.assertEqual(len(self.edus), 1)
         self.check_device_update_edu(self.edus.pop(0), u1, "D2", stream_id)
 
+    def test_dont_send_device_updates_for_remote_users(self):
+        """Check that we don't send device updates for remote users"""
+
+        # Send the server a device list EDU for the other user, this will cause
+        # it to try and resync the device lists.
+        self.hs.get_federation_transport_client().query_user_devices.return_value = (
+            defer.succeed(
+                {
+                    "stream_id": "1",
+                    "user_id": "@user2:host2",
+                    "devices": [{"device_id": "D1"}],
+                }
+            )
+        )
+
+        self.get_success(
+            self.hs.get_device_handler().device_list_updater.incoming_device_list_update(
+                "host2",
+                {
+                    "user_id": "@user2:host2",
+                    "device_id": "D1",
+                    "stream_id": "1",
+                    "prev_ids": [],
+                },
+            )
+        )
+
+        self.reactor.advance(1)
+
+        # We shouldn't see an EDU for that update
+        self.assertEqual(self.edus, [])
+
+        # Check that we did successfully process the inbound EDU (otherwise this
+        # test would pass if we failed to process the EDU)
+        devices = self.get_success(
+            self.hs.get_datastores().main.get_cached_devices_for_user("@user2:host2")
+        )
+        self.assertIn("D1", devices)
+
     def test_upload_signatures(self):
         """Uploading signatures on some devices should produce updates for that user"""
 
diff --git a/tests/federation/test_federation_server.py b/tests/federation/test_federation_server.py
index 30e7e5093a..b19365b81a 100644
--- a/tests/federation/test_federation_server.py
+++ b/tests/federation/test_federation_server.py
@@ -104,58 +104,21 @@ class ServerACLsTestCase(unittest.TestCase):
 
 
 class StateQueryTests(unittest.FederatingHomeserverTestCase):
-
     servlets = [
         admin.register_servlets,
         room.register_servlets,
         login.register_servlets,
     ]
 
-    def test_without_event_id(self):
-        """
-        Querying v1/state/<room_id> without an event ID will return the current
-        known state.
-        """
-        u1 = self.register_user("u1", "pass")
-        u1_token = self.login("u1", "pass")
-
-        room_1 = self.helper.create_room_as(u1, tok=u1_token)
-        self.inject_room_member(room_1, "@user:other.example.com", "join")
-
-        channel = self.make_signed_federation_request(
-            "GET", "/_matrix/federation/v1/state/%s" % (room_1,)
-        )
-        self.assertEqual(200, channel.code, channel.result)
-
-        self.assertEqual(
-            channel.json_body["room_version"],
-            self.hs.config.server.default_room_version.identifier,
-        )
-
-        members = set(
-            map(
-                lambda x: x["state_key"],
-                filter(
-                    lambda x: x["type"] == "m.room.member", channel.json_body["pdus"]
-                ),
-            )
-        )
-
-        self.assertEqual(members, {"@user:other.example.com", u1})
-        self.assertEqual(len(channel.json_body["pdus"]), 6)
-
     def test_needs_to_be_in_room(self):
-        """
-        Querying v1/state/<room_id> requires the server
-        be in the room to provide data.
-        """
+        """/v1/state/<room_id> requires the server to be in the room"""
         u1 = self.register_user("u1", "pass")
         u1_token = self.login("u1", "pass")
 
         room_1 = self.helper.create_room_as(u1, tok=u1_token)
 
         channel = self.make_signed_federation_request(
-            "GET", "/_matrix/federation/v1/state/%s" % (room_1,)
+            "GET", "/_matrix/federation/v1/state/%s?event_id=xyz" % (room_1,)
         )
         self.assertEqual(403, channel.code, channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
diff --git a/tests/handlers/test_presence.py b/tests/handlers/test_presence.py
index b2ed9cbe37..c96dc6caf2 100644
--- a/tests/handlers/test_presence.py
+++ b/tests/handlers/test_presence.py
@@ -657,6 +657,85 @@ class PresenceHandlerTestCase(unittest.HomeserverTestCase):
         # Mark user as online and `status_msg = None`
         self._set_presencestate_with_status_msg(user_id, PresenceState.ONLINE, None)
 
+    def test_set_presence_from_syncing_not_set(self):
+        """Test that presence is not set by syncing if affect_presence is false"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, False, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should still be unavailable
+        self.assertEqual(state.state, PresenceState.UNAVAILABLE)
+        # and status message should still be the same
+        self.assertEqual(state.status_msg, status_msg)
+
+    def test_set_presence_from_syncing_is_set(self):
+        """Test that presence is set by syncing if affect_presence is true"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should now be online
+        self.assertEqual(state.state, PresenceState.ONLINE)
+
+    def test_set_presence_from_syncing_keeps_status(self):
+        """Test that presence set by syncing retains status message"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # our status message should be the same as it was before
+        self.assertEqual(state.status_msg, status_msg)
+
+    def test_set_presence_from_syncing_keeps_busy(self):
+        """Test that presence set by syncing doesn't affect busy status"""
+        # while this isn't the default
+        self.presence_handler._busy_presence_enabled = True
+
+        user_id = "@test:server"
+        status_msg = "I'm busy!"
+
+        self._set_presencestate_with_status_msg(user_id, PresenceState.BUSY, status_msg)
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should still be busy
+        self.assertEqual(state.state, PresenceState.BUSY)
+
     def _set_presencestate_with_status_msg(
         self, user_id: str, state: str, status_msg: Optional[str]
     ):
diff --git a/tests/rest/admin/test_admin.py b/tests/rest/admin/test_admin.py
index 849d00ab4d..40571b753a 100644
--- a/tests/rest/admin/test_admin.py
+++ b/tests/rest/admin/test_admin.py
@@ -63,6 +63,7 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
         self.other_user = self.register_user("user", "pass")
         self.other_user_token = self.login("user", "pass")
 
+    @unittest.override_config({"experimental_features": {"groups_enabled": True}})
     def test_delete_group(self) -> None:
         # Create a new group
         channel = self.make_request(
diff --git a/tests/rest/client/test_login.py b/tests/rest/client/test_login.py
index 090d2d0a29..0a3d017dc9 100644
--- a/tests/rest/client/test_login.py
+++ b/tests/rest/client/test_login.py
@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import json
 import time
 import urllib.parse
 from typing import Any, Dict, List, Optional, Union
@@ -384,6 +384,31 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         channel = self.make_request(b"POST", "/logout/all", access_token=access_token)
         self.assertEqual(channel.result["code"], b"200", channel.result)
 
+    def test_login_with_overly_long_device_id_fails(self) -> None:
+        self.register_user("mickey", "cheese")
+
+        # create a device_id longer than 512 characters
+        device_id = "yolo" * 512
+
+        body = {
+            "type": "m.login.password",
+            "user": "mickey",
+            "password": "cheese",
+            "device_id": device_id,
+        }
+
+        # make a login request with the bad device_id
+        channel = self.make_request(
+            "POST",
+            "/_matrix/client/v3/login",
+            json.dumps(body).encode("utf8"),
+            custom_headers=None,
+        )
+
+        # test that the login fails with the correct error code
+        self.assertEqual(channel.code, 400)
+        self.assertEqual(channel.json_body["errcode"], "M_INVALID_PARAM")
+
 
 @skip_unless(has_saml2 and HAS_OIDC, "Requires SAML2 and OIDC")
 class MultiSSOTestCase(unittest.HomeserverTestCase):
diff --git a/tests/rest/client/test_room_batch.py b/tests/rest/client/test_room_batch.py
index 44f333a0ee..41a1bf6d89 100644
--- a/tests/rest/client/test_room_batch.py
+++ b/tests/rest/client/test_room_batch.py
@@ -7,9 +7,9 @@ from twisted.test.proto_helpers import MemoryReactor
 from synapse.api.constants import EventContentFields, EventTypes
 from synapse.appservice import ApplicationService
 from synapse.rest import admin
-from synapse.rest.client import login, register, room, room_batch
+from synapse.rest.client import login, register, room, room_batch, sync
 from synapse.server import HomeServer
-from synapse.types import JsonDict
+from synapse.types import JsonDict, RoomStreamToken
 from synapse.util import Clock
 
 from tests import unittest
@@ -63,6 +63,7 @@ class RoomBatchTestCase(unittest.HomeserverTestCase):
         room.register_servlets,
         register.register_servlets,
         login.register_servlets,
+        sync.register_servlets,
     ]
 
     def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
@@ -178,3 +179,123 @@ class RoomBatchTestCase(unittest.HomeserverTestCase):
             "Expected a single state_group to be returned by saw state_groups=%s"
             % (state_group_map.keys(),),
         )
+
+    @unittest.override_config({"experimental_features": {"msc2716_enabled": True}})
+    def test_sync_while_batch_importing(self) -> None:
+        """
+        Make sure that /sync correctly returns full room state when a user joins
+        during ongoing batch backfilling.
+        See: https://github.com/matrix-org/synapse/issues/12281
+        """
+        # Create user who will be invited & join room
+        user_id = self.register_user("beep", "test")
+        user_tok = self.login("beep", "test")
+
+        time_before_room = int(self.clock.time_msec())
+
+        # Create a room with some events
+        room_id, _, _, _ = self._create_test_room()
+        # Invite the user
+        self.helper.invite(
+            room_id, src=self.appservice.sender, tok=self.appservice.token, targ=user_id
+        )
+
+        # Create another room, send a bunch of events to advance the stream token
+        other_room_id = self.helper.create_room_as(
+            self.appservice.sender, tok=self.appservice.token
+        )
+        for _ in range(5):
+            self.helper.send_event(
+                room_id=other_room_id,
+                type=EventTypes.Message,
+                content={"msgtype": "m.text", "body": "C"},
+                tok=self.appservice.token,
+            )
+
+        # Join the room as the normal user
+        self.helper.join(room_id, user_id, tok=user_tok)
+
+        # Create an event to hang the historical batch from - In order to see
+        # the failure case originally reported in #12281, the historical batch
+        # must be hung from the most recent event in the room so the base
+        # insertion event ends up with the highest `topogological_ordering`
+        # (`depth`) in the room but will have a negative `stream_ordering`
+        # because it's a `historical` event. Previously, when assembling the
+        # `state` for the `/sync` response, the bugged logic would sort by
+        # `topological_ordering` descending and pick up the base insertion
+        # event because it has a negative `stream_ordering` below the given
+        # pagination token. Now we properly sort by `stream_ordering`
+        # descending which puts `historical` events with a negative
+        # `stream_ordering` way at the bottom and aren't selected as expected.
+        response = self.helper.send_event(
+            room_id=room_id,
+            type=EventTypes.Message,
+            content={
+                "msgtype": "m.text",
+                "body": "C",
+            },
+            tok=self.appservice.token,
+        )
+        event_to_hang_id = response["event_id"]
+
+        channel = self.make_request(
+            "POST",
+            "/_matrix/client/unstable/org.matrix.msc2716/rooms/%s/batch_send?prev_event_id=%s"
+            % (room_id, event_to_hang_id),
+            content={
+                "events": _create_message_events_for_batch_send_request(
+                    self.virtual_user_id, time_before_room, 3
+                ),
+                "state_events_at_start": _create_join_state_events_for_batch_send_request(
+                    [self.virtual_user_id], time_before_room
+                ),
+            },
+            access_token=self.appservice.token,
+        )
+        self.assertEqual(channel.code, 200, channel.result)
+
+        # Now we need to find the invite + join events stream tokens so we can sync between
+        main_store = self.hs.get_datastores().main
+        events, next_key = self.get_success(
+            main_store.get_recent_events_for_room(
+                room_id,
+                50,
+                end_token=main_store.get_room_max_token(),
+            ),
+        )
+        invite_event_position = None
+        for event in events:
+            if (
+                event.type == "m.room.member"
+                and event.content["membership"] == "invite"
+            ):
+                invite_event_position = self.get_success(
+                    main_store.get_topological_token_for_event(event.event_id)
+                )
+                break
+
+        assert invite_event_position is not None, "No invite event found"
+
+        # Remove the topological order from the token by re-creating w/stream only
+        invite_event_position = RoomStreamToken(None, invite_event_position.stream)
+
+        # Sync everything after this token
+        since_token = self.get_success(invite_event_position.to_string(main_store))
+        sync_response = self.make_request(
+            "GET",
+            f"/sync?since={since_token}",
+            access_token=user_tok,
+        )
+
+        # Assert that, for this room, the user was considered to have joined and thus
+        # receives the full state history
+        state_event_types = [
+            event["type"]
+            for event in sync_response.json_body["rooms"]["join"][room_id]["state"][
+                "events"
+            ]
+        ]
+
+        assert (
+            "m.room.create" in state_event_types
+        ), "Missing room full state in sync response"
diff --git a/tests/storage/test_devices.py b/tests/storage/test_devices.py
index d1227dd4ac..ccc3893869 100644
--- a/tests/storage/test_devices.py
+++ b/tests/storage/test_devices.py
@@ -21,6 +21,29 @@ class DeviceStoreTestCase(HomeserverTestCase):
     def prepare(self, reactor, clock, hs):
         self.store = hs.get_datastores().main
 
+    def add_device_change(self, user_id, device_ids, host):
+        """Add a device list change for the given device to
+        `device_lists_outbound_pokes` table.
+        """
+
+        for device_id in device_ids:
+            stream_id = self.get_success(
+                self.store.add_device_change_to_streams(
+                    "user_id", [device_id], ["!some:room"]
+                )
+            )
+
+            self.get_success(
+                self.store.add_device_list_outbound_pokes(
+                    user_id=user_id,
+                    device_id=device_id,
+                    room_id="!some:room",
+                    stream_id=stream_id,
+                    hosts=[host],
+                    context={},
+                )
+            )
+
     def test_store_new_device(self):
         self.get_success(
             self.store.store_device("user_id", "device_id", "display_name")
@@ -95,11 +118,7 @@ class DeviceStoreTestCase(HomeserverTestCase):
         device_ids = ["device_id1", "device_id2"]
 
         # Add two device updates with sequential `stream_id`s
-        self.get_success(
-            self.store.add_device_change_to_streams(
-                "user_id", device_ids, ["somehost"], ["!some:room"]
-            )
-        )
+        self.add_device_change("@user_id:test", device_ids, "somehost")
 
         # Get all device updates ever meant for this remote
         now_stream_id, device_updates = self.get_success(
@@ -123,11 +142,7 @@ class DeviceStoreTestCase(HomeserverTestCase):
             "device_id4",
             "device_id5",
         ]
-        self.get_success(
-            self.store.add_device_change_to_streams(
-                "user_id", device_ids, ["somehost"], ["!some:room"]
-            )
-        )
+        self.add_device_change("@user_id:test", device_ids, "somehost")
 
         # Get device updates meant for this remote
         next_stream_id, device_updates = self.get_success(
@@ -147,11 +162,7 @@ class DeviceStoreTestCase(HomeserverTestCase):
 
         # Add some more device updates to ensure it still resumes properly
         device_ids = ["device_id6", "device_id7"]
-        self.get_success(
-            self.store.add_device_change_to_streams(
-                "user_id", device_ids, ["somehost"], ["!some:room"]
-            )
-        )
+        self.add_device_change("@user_id:test", device_ids, "somehost")
 
         # Get the next batch of device updates
         next_stream_id, device_updates = self.get_success(
@@ -224,11 +235,7 @@ class DeviceStoreTestCase(HomeserverTestCase):
             "fakeSelfSigning",
         ]
 
-        self.get_success(
-            self.store.add_device_change_to_streams(
-                "@user_id:test", device_ids, ["somehost"], ["!some:room"]
-            )
-        )
+        self.add_device_change("@user_id:test", device_ids, "somehost")
 
         # Get device updates meant for this remote
         next_stream_id, device_updates = self.get_success(
diff --git a/tox.ini b/tox.ini
index b4ce400edf..4cd9dfb966 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py37, py38, py39, py310, check_codestyle, check_isort
+envlist = py37, py38, py39, py310
 
 # we require tox>=2.3.2 for the fix to https://github.com/tox-dev/tox/issues/208
 minversion = 2.3.2
@@ -32,20 +32,6 @@ deps =
     # install the "enum34" dependency of cryptography.
     pip>=10
 
-# directories/files we run the linters on.
-# TODO: this is now out of date; we will remove as part of poetry migration.
-lint_targets =
-    setup.py
-    synapse
-    tests
-    # annoyingly, black doesn't find these so we have to list them
-    scripts-dev
-    stubs
-    contrib
-    synmark
-    .ci
-    docker
-
 # default settings for all tox environments
 [testenv]
 deps =
@@ -116,18 +102,3 @@ setenv =
 commands =
     python -m synmark {posargs:}
 
-[testenv:check_codestyle]
-extras = lint
-commands =
-    python -m black --check --diff {[base]lint_targets}
-    flake8 {[base]lint_targets} {env:PEP8SUFFIX:}
-
-[testenv:check_isort]
-extras = lint
-commands = isort -c --df {[base]lint_targets}
-
-[testenv:mypy]
-deps =
-    {[base]deps}
-extras = all,mypy
-commands = mypy