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-rw-r--r--synapse/api/filtering.py117
-rw-r--r--synapse/app/_base.py8
-rw-r--r--synapse/app/admin_cmd.py4
-rw-r--r--synapse/app/generic_worker.py2
-rw-r--r--synapse/app/homeserver.py14
-rw-r--r--synapse/app/phone_stats_home.py8
-rw-r--r--synapse/config/_base.py2
-rw-r--r--synapse/config/server.py104
-rw-r--r--synapse/event_auth.py156
-rw-r--r--synapse/events/builder.py20
-rw-r--r--synapse/events/presence_router.py6
-rw-r--r--synapse/events/utils.py2
-rw-r--r--synapse/federation/federation_server.py5
-rw-r--r--synapse/federation/transport/server/__init__.py2
-rw-r--r--synapse/handlers/auth.py2
-rw-r--r--synapse/handlers/deactivate_account.py4
-rw-r--r--synapse/handlers/directory.py2
-rw-r--r--synapse/handlers/event_auth.py15
-rw-r--r--synapse/handlers/federation.py70
-rw-r--r--synapse/handlers/federation_event.py156
-rw-r--r--synapse/handlers/identity.py15
-rw-r--r--synapse/handlers/message.py79
-rw-r--r--synapse/handlers/pagination.py22
-rw-r--r--synapse/handlers/profile.py6
-rw-r--r--synapse/handlers/register.py15
-rw-r--r--synapse/handlers/room.py8
-rw-r--r--synapse/handlers/room_member.py16
-rw-r--r--synapse/handlers/search.py2
-rw-r--r--synapse/handlers/send_email.py9
-rw-r--r--synapse/handlers/ui_auth/checkers.py14
-rw-r--r--synapse/handlers/user_directory.py29
-rw-r--r--synapse/http/matrixfederationclient.py10
-rw-r--r--synapse/logging/opentracing.py1
-rw-r--r--synapse/replication/tcp/handler.py8
-rw-r--r--synapse/replication/tcp/redis.py8
-rw-r--r--synapse/replication/tcp/resource.py2
-rw-r--r--synapse/rest/admin/users.py4
-rw-r--r--synapse/rest/client/account.py40
-rw-r--r--synapse/rest/client/auth.py6
-rw-r--r--synapse/rest/client/capabilities.py10
-rw-r--r--synapse/rest/client/filter.py2
-rw-r--r--synapse/rest/client/login.py6
-rw-r--r--synapse/rest/client/profile.py6
-rw-r--r--synapse/rest/client/register.py32
-rw-r--r--synapse/rest/client/room.py2
-rw-r--r--synapse/rest/client/room_batch.py6
-rw-r--r--synapse/rest/client/shared_rooms.py2
-rw-r--r--synapse/rest/client/sync.py2
-rw-r--r--synapse/rest/client/voip.py2
-rw-r--r--synapse/rest/media/v1/preview_url_resource.py74
-rw-r--r--synapse/rest/well_known.py4
-rw-r--r--synapse/server_notices/resource_limits_server_notices.py8
-rw-r--r--synapse/state/v1.py8
-rw-r--r--synapse/state/v2.py4
-rw-r--r--synapse/storage/databases/main/censor_events.py8
-rw-r--r--synapse/storage/databases/main/client_ips.py2
-rw-r--r--synapse/storage/databases/main/events.py24
-rw-r--r--synapse/storage/databases/main/filtering.py8
-rw-r--r--synapse/storage/databases/main/monthly_active_users.py36
-rw-r--r--synapse/storage/databases/main/registration.py4
-rw-r--r--synapse/storage/databases/main/room.py8
-rw-r--r--synapse/storage/databases/main/room_batch.py6
-rw-r--r--synapse/storage/databases/main/search.py4
-rw-r--r--synapse/storage/databases/main/user_directory.py48
-rw-r--r--synapse/storage/prepare_database.py2
-rw-r--r--synapse/storage/schema/__init__.py6
-rw-r--r--synapse/util/__init__.py8
-rw-r--r--synapse/util/threepids.py4
68 files changed, 769 insertions, 560 deletions
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index ad1ff6a9df..20e91a115d 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -15,7 +15,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import json
-from typing import List
+from typing import (
+    TYPE_CHECKING,
+    Awaitable,
+    Container,
+    Iterable,
+    List,
+    Optional,
+    Set,
+    TypeVar,
+    Union,
+)
 
 import jsonschema
 from jsonschema import FormatChecker
@@ -23,7 +33,11 @@ from jsonschema import FormatChecker
 from synapse.api.constants import EventContentFields
 from synapse.api.errors import SynapseError
 from synapse.api.presence import UserPresenceState
-from synapse.types import RoomID, UserID
+from synapse.events import EventBase
+from synapse.types import JsonDict, RoomID, UserID
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
 
 FILTER_SCHEMA = {
     "additionalProperties": False,
@@ -120,25 +134,29 @@ USER_FILTER_SCHEMA = {
 
 
 @FormatChecker.cls_checks("matrix_room_id")
-def matrix_room_id_validator(room_id_str):
+def matrix_room_id_validator(room_id_str: str) -> RoomID:
     return RoomID.from_string(room_id_str)
 
 
 @FormatChecker.cls_checks("matrix_user_id")
-def matrix_user_id_validator(user_id_str):
+def matrix_user_id_validator(user_id_str: str) -> UserID:
     return UserID.from_string(user_id_str)
 
 
 class Filtering:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__()
         self.store = hs.get_datastore()
 
-    async def get_user_filter(self, user_localpart, filter_id):
+    async def get_user_filter(
+        self, user_localpart: str, filter_id: Union[int, str]
+    ) -> "FilterCollection":
         result = await self.store.get_user_filter(user_localpart, filter_id)
         return FilterCollection(result)
 
-    def add_user_filter(self, user_localpart, user_filter):
+    def add_user_filter(
+        self, user_localpart: str, user_filter: JsonDict
+    ) -> Awaitable[int]:
         self.check_valid_filter(user_filter)
         return self.store.add_user_filter(user_localpart, user_filter)
 
@@ -146,13 +164,13 @@ class Filtering:
     #   replace_user_filter at some point? There's no REST API specified for
     #   them however
 
-    def check_valid_filter(self, user_filter_json):
+    def check_valid_filter(self, user_filter_json: JsonDict) -> None:
         """Check if the provided filter is valid.
 
         This inspects all definitions contained within the filter.
 
         Args:
-            user_filter_json(dict): The filter
+            user_filter_json: The filter
         Raises:
             SynapseError: If the filter is not valid.
         """
@@ -167,8 +185,12 @@ class Filtering:
             raise SynapseError(400, str(e))
 
 
+# Filters work across events, presence EDUs, and account data.
+FilterEvent = TypeVar("FilterEvent", EventBase, UserPresenceState, JsonDict)
+
+
 class FilterCollection:
-    def __init__(self, filter_json):
+    def __init__(self, filter_json: JsonDict):
         self._filter_json = filter_json
 
         room_filter_json = self._filter_json.get("room", {})
@@ -188,25 +210,25 @@ class FilterCollection:
         self.event_fields = filter_json.get("event_fields", [])
         self.event_format = filter_json.get("event_format", "client")
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return "<FilterCollection %s>" % (json.dumps(self._filter_json),)
 
-    def get_filter_json(self):
+    def get_filter_json(self) -> JsonDict:
         return self._filter_json
 
-    def timeline_limit(self):
+    def timeline_limit(self) -> int:
         return self._room_timeline_filter.limit()
 
-    def presence_limit(self):
+    def presence_limit(self) -> int:
         return self._presence_filter.limit()
 
-    def ephemeral_limit(self):
+    def ephemeral_limit(self) -> int:
         return self._room_ephemeral_filter.limit()
 
-    def lazy_load_members(self):
+    def lazy_load_members(self) -> bool:
         return self._room_state_filter.lazy_load_members()
 
-    def include_redundant_members(self):
+    def include_redundant_members(self) -> bool:
         return self._room_state_filter.include_redundant_members()
 
     def filter_presence(self, events):
@@ -218,29 +240,31 @@ class FilterCollection:
     def filter_room_state(self, events):
         return self._room_state_filter.filter(self._room_filter.filter(events))
 
-    def filter_room_timeline(self, events):
+    def filter_room_timeline(self, events: Iterable[FilterEvent]) -> List[FilterEvent]:
         return self._room_timeline_filter.filter(self._room_filter.filter(events))
 
-    def filter_room_ephemeral(self, events):
+    def filter_room_ephemeral(self, events: Iterable[FilterEvent]) -> List[FilterEvent]:
         return self._room_ephemeral_filter.filter(self._room_filter.filter(events))
 
-    def filter_room_account_data(self, events):
+    def filter_room_account_data(
+        self, events: Iterable[FilterEvent]
+    ) -> List[FilterEvent]:
         return self._room_account_data.filter(self._room_filter.filter(events))
 
-    def blocks_all_presence(self):
+    def blocks_all_presence(self) -> bool:
         return (
             self._presence_filter.filters_all_types()
             or self._presence_filter.filters_all_senders()
         )
 
-    def blocks_all_room_ephemeral(self):
+    def blocks_all_room_ephemeral(self) -> bool:
         return (
             self._room_ephemeral_filter.filters_all_types()
             or self._room_ephemeral_filter.filters_all_senders()
             or self._room_ephemeral_filter.filters_all_rooms()
         )
 
-    def blocks_all_room_timeline(self):
+    def blocks_all_room_timeline(self) -> bool:
         return (
             self._room_timeline_filter.filters_all_types()
             or self._room_timeline_filter.filters_all_senders()
@@ -249,7 +273,7 @@ class FilterCollection:
 
 
 class Filter:
-    def __init__(self, filter_json):
+    def __init__(self, filter_json: JsonDict):
         self.filter_json = filter_json
 
         self.types = self.filter_json.get("types", None)
@@ -266,20 +290,20 @@ class Filter:
         self.labels = self.filter_json.get("org.matrix.labels", None)
         self.not_labels = self.filter_json.get("org.matrix.not_labels", [])
 
-    def filters_all_types(self):
+    def filters_all_types(self) -> bool:
         return "*" in self.not_types
 
-    def filters_all_senders(self):
+    def filters_all_senders(self) -> bool:
         return "*" in self.not_senders
 
-    def filters_all_rooms(self):
+    def filters_all_rooms(self) -> bool:
         return "*" in self.not_rooms
 
-    def check(self, event):
+    def check(self, event: FilterEvent) -> bool:
         """Checks whether the filter matches the given event.
 
         Returns:
-            bool: True if the event matches
+            True if the event matches
         """
         # We usually get the full "events" as dictionaries coming through,
         # except for presence which actually gets passed around as its own
@@ -305,18 +329,25 @@ class Filter:
             room_id = event.get("room_id", None)
             ev_type = event.get("type", None)
 
-            content = event.get("content", {})
+            content = event.get("content") or {}
             # check if there is a string url field in the content for filtering purposes
             contains_url = isinstance(content.get("url"), str)
             labels = content.get(EventContentFields.LABELS, [])
 
         return self.check_fields(room_id, sender, ev_type, labels, contains_url)
 
-    def check_fields(self, room_id, sender, event_type, labels, contains_url):
+    def check_fields(
+        self,
+        room_id: Optional[str],
+        sender: Optional[str],
+        event_type: Optional[str],
+        labels: Container[str],
+        contains_url: bool,
+    ) -> bool:
         """Checks whether the filter matches the given event fields.
 
         Returns:
-            bool: True if the event fields match
+            True if the event fields match
         """
         literal_keys = {
             "rooms": lambda v: room_id == v,
@@ -343,14 +374,14 @@ class Filter:
 
         return True
 
-    def filter_rooms(self, room_ids):
+    def filter_rooms(self, room_ids: Iterable[str]) -> Set[str]:
         """Apply the 'rooms' filter to a given list of rooms.
 
         Args:
-            room_ids (list): A list of room_ids.
+            room_ids: A list of room_ids.
 
         Returns:
-            list: A list of room_ids that match the filter
+            A list of room_ids that match the filter
         """
         room_ids = set(room_ids)
 
@@ -363,23 +394,23 @@ class Filter:
 
         return room_ids
 
-    def filter(self, events):
+    def filter(self, events: Iterable[FilterEvent]) -> List[FilterEvent]:
         return list(filter(self.check, events))
 
-    def limit(self):
+    def limit(self) -> int:
         return self.filter_json.get("limit", 10)
 
-    def lazy_load_members(self):
+    def lazy_load_members(self) -> bool:
         return self.filter_json.get("lazy_load_members", False)
 
-    def include_redundant_members(self):
+    def include_redundant_members(self) -> bool:
         return self.filter_json.get("include_redundant_members", False)
 
-    def with_room_ids(self, room_ids):
+    def with_room_ids(self, room_ids: Iterable[str]) -> "Filter":
         """Returns a new filter with the given room IDs appended.
 
         Args:
-            room_ids (iterable[unicode]): The room_ids to add
+            room_ids: The room_ids to add
 
         Returns:
             filter: A new filter including the given rooms and the old
@@ -390,8 +421,8 @@ class Filter:
         return newFilter
 
 
-def _matches_wildcard(actual_value, filter_value):
-    if filter_value.endswith("*"):
+def _matches_wildcard(actual_value: Optional[str], filter_value: str) -> bool:
+    if filter_value.endswith("*") and isinstance(actual_value, str):
         type_prefix = filter_value[:-1]
         return actual_value.startswith(type_prefix)
     else:
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index 548f6dcde9..749bc1deb9 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -86,11 +86,11 @@ def start_worker_reactor(appname, config, run_command=reactor.run):
 
     start_reactor(
         appname,
-        soft_file_limit=config.soft_file_limit,
-        gc_thresholds=config.gc_thresholds,
+        soft_file_limit=config.server.soft_file_limit,
+        gc_thresholds=config.server.gc_thresholds,
         pid_file=config.worker.worker_pid_file,
         daemonize=config.worker.worker_daemonize,
-        print_pidfile=config.print_pidfile,
+        print_pidfile=config.server.print_pidfile,
         logger=logger,
         run_command=run_command,
     )
@@ -298,7 +298,7 @@ def refresh_certificate(hs):
     Refresh the TLS certificates that Synapse is using by re-reading them from
     disk and updating the TLS context factories to use them.
     """
-    if not hs.config.has_tls_listener():
+    if not hs.config.server.has_tls_listener():
         return
 
     hs.config.read_certificate_from_disk()
diff --git a/synapse/app/admin_cmd.py b/synapse/app/admin_cmd.py
index f2c5b75247..556bcc124e 100644
--- a/synapse/app/admin_cmd.py
+++ b/synapse/app/admin_cmd.py
@@ -195,14 +195,14 @@ def start(config_options):
         config.logging.no_redirect_stdio = True
 
     # Explicitly disable background processes
-    config.update_user_directory = False
+    config.server.update_user_directory = False
     config.worker.run_background_tasks = False
     config.start_pushers = False
     config.pusher_shard_config.instances = []
     config.send_federation = False
     config.federation_shard_config.instances = []
 
-    synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts
+    synapse.events.USE_FROZEN_DICTS = config.server.use_frozen_dicts
 
     ss = AdminCmdServer(
         config.server.server_name,
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index 3036e1b4a0..7489f31d9a 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -462,7 +462,7 @@ def start(config_options):
         # For other worker types we force this to off.
         config.server.update_user_directory = False
 
-    synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts
+    synapse.events.USE_FROZEN_DICTS = config.server.use_frozen_dicts
     synapse.util.caches.TRACK_MEMORY_USAGE = config.caches.track_memory_usage
 
     if config.server.gc_seconds:
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 205831dcda..2b2d4bbf83 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -248,7 +248,7 @@ class SynapseHomeServer(HomeServer):
             resources[SERVER_KEY_V2_PREFIX] = KeyApiV2Resource(self)
 
         if name == "webclient":
-            webclient_loc = self.config.web_client_location
+            webclient_loc = self.config.server.web_client_location
 
             if webclient_loc is None:
                 logger.warning(
@@ -343,7 +343,7 @@ def setup(config_options):
         # generating config files and shouldn't try to continue.
         sys.exit(0)
 
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
+    events.USE_FROZEN_DICTS = config.server.use_frozen_dicts
     synapse.util.caches.TRACK_MEMORY_USAGE = config.caches.track_memory_usage
 
     if config.server.gc_seconds:
@@ -439,11 +439,11 @@ def run(hs):
 
     _base.start_reactor(
         "synapse-homeserver",
-        soft_file_limit=hs.config.soft_file_limit,
-        gc_thresholds=hs.config.gc_thresholds,
-        pid_file=hs.config.pid_file,
-        daemonize=hs.config.daemonize,
-        print_pidfile=hs.config.print_pidfile,
+        soft_file_limit=hs.config.server.soft_file_limit,
+        gc_thresholds=hs.config.server.gc_thresholds,
+        pid_file=hs.config.server.pid_file,
+        daemonize=hs.config.server.daemonize,
+        print_pidfile=hs.config.server.print_pidfile,
         logger=logger,
     )
 
diff --git a/synapse/app/phone_stats_home.py b/synapse/app/phone_stats_home.py
index 49e7a45e5c..fcd01e833c 100644
--- a/synapse/app/phone_stats_home.py
+++ b/synapse/app/phone_stats_home.py
@@ -74,7 +74,7 @@ async def phone_stats_home(hs, stats, stats_process=_stats_process):
     store = hs.get_datastore()
 
     stats["homeserver"] = hs.config.server.server_name
-    stats["server_context"] = hs.config.server_context
+    stats["server_context"] = hs.config.server.server_context
     stats["timestamp"] = now
     stats["uptime_seconds"] = uptime
     version = sys.version_info
@@ -171,7 +171,7 @@ def start_phone_stats_home(hs):
         current_mau_count_by_service = {}
         reserved_users = ()
         store = hs.get_datastore()
-        if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
+        if hs.config.server.limit_usage_by_mau or hs.config.server.mau_stats_only:
             current_mau_count = await store.get_monthly_active_count()
             current_mau_count_by_service = (
                 await store.get_monthly_active_count_by_service()
@@ -183,9 +183,9 @@ def start_phone_stats_home(hs):
             current_mau_by_service_gauge.labels(app_service).set(float(count))
 
         registered_reserved_users_mau_gauge.set(float(len(reserved_users)))
-        max_mau_gauge.set(float(hs.config.max_mau_value))
+        max_mau_gauge.set(float(hs.config.server.max_mau_value))
 
-    if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
+    if hs.config.server.limit_usage_by_mau or hs.config.server.mau_stats_only:
         generate_monthly_active_users()
         clock.looping_call(generate_monthly_active_users, 5 * 60 * 1000)
     # End of monthly active user settings
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index d974a1a2a8..26152b0924 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -327,7 +327,7 @@ class RootConfig:
         """
         Redirect lookups on this object either to config objects, or values on
         config objects, so that `config.tls.blah` works, as well as legacy uses
-        of things like `config.server_name`. It will first look up the config
+        of things like `config.server.server_name`. It will first look up the config
         section name, and then values on those config classes.
         """
         if item in self._configs.keys():
diff --git a/synapse/config/server.py b/synapse/config/server.py
index ad8715da29..818b806357 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -1,6 +1,4 @@
-# Copyright 2014-2016 OpenMarket Ltd
-# Copyright 2017-2018 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2014-2021 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,7 +17,7 @@ import logging
 import os.path
 import re
 from textwrap import indent
-from typing import Any, Dict, Iterable, List, Optional, Set, Tuple
+from typing import Any, Dict, Iterable, List, Optional, Set, Tuple, Union
 
 import attr
 import yaml
@@ -184,49 +182,74 @@ KNOWN_RESOURCES = {
 
 @attr.s(frozen=True)
 class HttpResourceConfig:
-    names = attr.ib(
-        type=List[str],
+    names: List[str] = attr.ib(
         factory=list,
         validator=attr.validators.deep_iterable(attr.validators.in_(KNOWN_RESOURCES)),  # type: ignore
     )
-    compress = attr.ib(
-        type=bool,
+    compress: bool = attr.ib(
         default=False,
         validator=attr.validators.optional(attr.validators.instance_of(bool)),  # type: ignore[arg-type]
     )
 
 
-@attr.s(frozen=True)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
 class HttpListenerConfig:
     """Object describing the http-specific parts of the config of a listener"""
 
-    x_forwarded = attr.ib(type=bool, default=False)
-    resources = attr.ib(type=List[HttpResourceConfig], factory=list)
-    additional_resources = attr.ib(type=Dict[str, dict], factory=dict)
-    tag = attr.ib(type=str, default=None)
+    x_forwarded: bool = False
+    resources: List[HttpResourceConfig] = attr.ib(factory=list)
+    additional_resources: Dict[str, dict] = attr.ib(factory=dict)
+    tag: Optional[str] = None
 
 
-@attr.s(frozen=True)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
 class ListenerConfig:
     """Object describing the configuration of a single listener."""
 
-    port = attr.ib(type=int, validator=attr.validators.instance_of(int))
-    bind_addresses = attr.ib(type=List[str])
-    type = attr.ib(type=str, validator=attr.validators.in_(KNOWN_LISTENER_TYPES))
-    tls = attr.ib(type=bool, default=False)
+    port: int = attr.ib(validator=attr.validators.instance_of(int))
+    bind_addresses: List[str]
+    type: str = attr.ib(validator=attr.validators.in_(KNOWN_LISTENER_TYPES))
+    tls: bool = False
 
     # http_options is only populated if type=http
-    http_options = attr.ib(type=Optional[HttpListenerConfig], default=None)
+    http_options: Optional[HttpListenerConfig] = None
 
 
-@attr.s(frozen=True)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
 class ManholeConfig:
     """Object describing the configuration of the manhole"""
 
-    username = attr.ib(type=str, validator=attr.validators.instance_of(str))
-    password = attr.ib(type=str, validator=attr.validators.instance_of(str))
-    priv_key = attr.ib(type=Optional[Key])
-    pub_key = attr.ib(type=Optional[Key])
+    username: str = attr.ib(validator=attr.validators.instance_of(str))
+    password: str = attr.ib(validator=attr.validators.instance_of(str))
+    priv_key: Optional[Key]
+    pub_key: Optional[Key]
+
+
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RetentionConfig:
+    """Object describing the configuration of the manhole"""
+
+    interval: int
+    shortest_max_lifetime: Optional[int]
+    longest_max_lifetime: Optional[int]
+
+
+@attr.s(frozen=True)
+class LimitRemoteRoomsConfig:
+    enabled: bool = attr.ib(validator=attr.validators.instance_of(bool), default=False)
+    complexity: Union[float, int] = attr.ib(
+        validator=attr.validators.instance_of(
+            (float, int)  # type: ignore[arg-type] # noqa
+        ),
+        default=1.0,
+    )
+    complexity_error: str = attr.ib(
+        validator=attr.validators.instance_of(str),
+        default=ROOM_COMPLEXITY_TOO_GREAT,
+    )
+    admins_can_join: bool = attr.ib(
+        validator=attr.validators.instance_of(bool), default=False
+    )
 
 
 class ServerConfig(Config):
@@ -519,7 +542,7 @@ class ServerConfig(Config):
                 " greater than 'allowed_lifetime_max'"
             )
 
-        self.retention_purge_jobs: List[Dict[str, Optional[int]]] = []
+        self.retention_purge_jobs: List[RetentionConfig] = []
         for purge_job_config in retention_config.get("purge_jobs", []):
             interval_config = purge_job_config.get("interval")
 
@@ -553,20 +576,12 @@ class ServerConfig(Config):
                 )
 
             self.retention_purge_jobs.append(
-                {
-                    "interval": interval,
-                    "shortest_max_lifetime": shortest_max_lifetime,
-                    "longest_max_lifetime": longest_max_lifetime,
-                }
+                RetentionConfig(interval, shortest_max_lifetime, longest_max_lifetime)
             )
 
         if not self.retention_purge_jobs:
             self.retention_purge_jobs = [
-                {
-                    "interval": self.parse_duration("1d"),
-                    "shortest_max_lifetime": None,
-                    "longest_max_lifetime": None,
-                }
+                RetentionConfig(self.parse_duration("1d"), None, None)
             ]
 
         self.listeners = [parse_listener_def(x) for x in config.get("listeners", [])]
@@ -591,25 +606,6 @@ class ServerConfig(Config):
         self.gc_thresholds = read_gc_thresholds(config.get("gc_thresholds", None))
         self.gc_seconds = self.read_gc_intervals(config.get("gc_min_interval", None))
 
-        @attr.s
-        class LimitRemoteRoomsConfig:
-            enabled = attr.ib(
-                validator=attr.validators.instance_of(bool), default=False
-            )
-            complexity = attr.ib(
-                validator=attr.validators.instance_of(
-                    (float, int)  # type: ignore[arg-type] # noqa
-                ),
-                default=1.0,
-            )
-            complexity_error = attr.ib(
-                validator=attr.validators.instance_of(str),
-                default=ROOM_COMPLEXITY_TOO_GREAT,
-            )
-            admins_can_join = attr.ib(
-                validator=attr.validators.instance_of(bool), default=False
-            )
-
         self.limit_remote_rooms = LimitRemoteRoomsConfig(
             **(config.get("limit_remote_rooms") or {})
         )
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index 650402836c..ca0293a3dc 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -41,42 +41,112 @@ from synapse.types import StateMap, UserID, get_domain_from_id
 logger = logging.getLogger(__name__)
 
 
-def check(
-    room_version_obj: RoomVersion,
-    event: EventBase,
-    auth_events: StateMap[EventBase],
-    do_sig_check: bool = True,
-    do_size_check: bool = True,
+def validate_event_for_room_version(
+    room_version_obj: RoomVersion, event: EventBase
 ) -> None:
-    """Checks if this event is correctly authed.
+    """Ensure that the event complies with the limits, and has the right signatures
+
+    NB: does not *validate* the signatures - it assumes that any signatures present
+    have already been checked.
+
+    NB: it does not check that the event satisfies the auth rules (that is done in
+    check_auth_rules_for_event) - these tests are independent of the rest of the state
+    in the room.
+
+    NB: This is used to check events that have been received over federation. As such,
+    it can only enforce the checks specified in the relevant room version, to avoid
+    a split-brain situation where some servers accept such events, and others reject
+    them.
+
+    TODO: consider moving this into EventValidator
 
     Args:
-        room_version_obj: the version of the room
-        event: the event being checked.
-        auth_events: the existing room state.
-        do_sig_check: True if it should be verified that the sending server
-            signed the event.
-        do_size_check: True if the size of the event fields should be verified.
+        room_version_obj: the version of the room which contains this event
+        event: the event to be checked
 
     Raises:
-        AuthError if the checks fail
-
-    Returns:
-         if the auth checks pass.
+        SynapseError if there is a problem with the event
     """
-    assert isinstance(auth_events, dict)
-
-    if do_size_check:
-        _check_size_limits(event)
+    _check_size_limits(event)
 
     if not hasattr(event, "room_id"):
         raise AuthError(500, "Event has no room_id: %s" % event)
 
-    room_id = event.room_id
+    # check that the event has the correct signatures
+    sender_domain = get_domain_from_id(event.sender)
+
+    is_invite_via_3pid = (
+        event.type == EventTypes.Member
+        and event.membership == Membership.INVITE
+        and "third_party_invite" in event.content
+    )
+
+    # Check the sender's domain has signed the event
+    if not event.signatures.get(sender_domain):
+        # We allow invites via 3pid to have a sender from a different
+        # HS, as the sender must match the sender of the original
+        # 3pid invite. This is checked further down with the
+        # other dedicated membership checks.
+        if not is_invite_via_3pid:
+            raise AuthError(403, "Event not signed by sender's server")
+
+    if event.format_version in (EventFormatVersions.V1,):
+        # Only older room versions have event IDs to check.
+        event_id_domain = get_domain_from_id(event.event_id)
+
+        # Check the origin domain has signed the event
+        if not event.signatures.get(event_id_domain):
+            raise AuthError(403, "Event not signed by sending server")
+
+    is_invite_via_allow_rule = (
+        room_version_obj.msc3083_join_rules
+        and event.type == EventTypes.Member
+        and event.membership == Membership.JOIN
+        and EventContentFields.AUTHORISING_USER in event.content
+    )
+    if is_invite_via_allow_rule:
+        authoriser_domain = get_domain_from_id(
+            event.content[EventContentFields.AUTHORISING_USER]
+        )
+        if not event.signatures.get(authoriser_domain):
+            raise AuthError(403, "Event not signed by authorising server")
+
+
+def check_auth_rules_for_event(
+    room_version_obj: RoomVersion, event: EventBase, auth_events: StateMap[EventBase]
+) -> None:
+    """Check that an event complies with the auth rules
+
+    Checks whether an event passes the auth rules with a given set of state events
+
+    Assumes that we have already checked that the event is the right shape (it has
+    enough signatures, has a room ID, etc). In other words:
+
+     - it's fine for use in state resolution, when we have already decided whether to
+       accept the event or not, and are now trying to decide whether it should make it
+       into the room state
+
+     - when we're doing the initial event auth, it is only suitable in combination with
+       a bunch of other tests.
+
+    Args:
+        room_version_obj: the version of the room
+        event: the event being checked.
+        auth_events: the room state to check the events against.
+
+    Raises:
+        AuthError if the checks fail
+    """
+    assert isinstance(auth_events, dict)
 
     # We need to ensure that the auth events are actually for the same room, to
     # stop people from using powers they've been granted in other rooms for
     # example.
+    #
+    # Arguably we don't need to do this when we're just doing state res, as presumably
+    # the state res algorithm isn't silly enough to give us events from different rooms.
+    # Still, it's easier to do it anyway.
+    room_id = event.room_id
     for auth_event in auth_events.values():
         if auth_event.room_id != room_id:
             raise AuthError(
@@ -85,44 +155,12 @@ def check(
                 "which is in room %s"
                 % (event.event_id, room_id, auth_event.event_id, auth_event.room_id),
             )
-
-    if do_sig_check:
-        sender_domain = get_domain_from_id(event.sender)
-
-        is_invite_via_3pid = (
-            event.type == EventTypes.Member
-            and event.membership == Membership.INVITE
-            and "third_party_invite" in event.content
-        )
-
-        # Check the sender's domain has signed the event
-        if not event.signatures.get(sender_domain):
-            # We allow invites via 3pid to have a sender from a different
-            # HS, as the sender must match the sender of the original
-            # 3pid invite. This is checked further down with the
-            # other dedicated membership checks.
-            if not is_invite_via_3pid:
-                raise AuthError(403, "Event not signed by sender's server")
-
-        if event.format_version in (EventFormatVersions.V1,):
-            # Only older room versions have event IDs to check.
-            event_id_domain = get_domain_from_id(event.event_id)
-
-            # Check the origin domain has signed the event
-            if not event.signatures.get(event_id_domain):
-                raise AuthError(403, "Event not signed by sending server")
-
-        is_invite_via_allow_rule = (
-            event.type == EventTypes.Member
-            and event.membership == Membership.JOIN
-            and EventContentFields.AUTHORISING_USER in event.content
-        )
-        if is_invite_via_allow_rule:
-            authoriser_domain = get_domain_from_id(
-                event.content[EventContentFields.AUTHORISING_USER]
+        if auth_event.rejected_reason:
+            raise AuthError(
+                403,
+                "During auth for event %s: found rejected event %s in the state"
+                % (event.event_id, auth_event.event_id),
             )
-            if not event.signatures.get(authoriser_domain):
-                raise AuthError(403, "Event not signed by authorising server")
 
     # Implementation of https://matrix.org/docs/spec/rooms/v1#authorization-rules
     #
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index 87e2bb123b..50f2a4c1f4 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -18,10 +18,8 @@ import attr
 from nacl.signing import SigningKey
 
 from synapse.api.constants import MAX_DEPTH
-from synapse.api.errors import UnsupportedRoomVersionError
 from synapse.api.room_versions import (
     KNOWN_EVENT_FORMAT_VERSIONS,
-    KNOWN_ROOM_VERSIONS,
     EventFormatVersions,
     RoomVersion,
 )
@@ -197,24 +195,6 @@ class EventBuilderFactory:
         self.state = hs.get_state_handler()
         self._event_auth_handler = hs.get_event_auth_handler()
 
-    def new(self, room_version: str, key_values: dict) -> EventBuilder:
-        """Generate an event builder appropriate for the given room version
-
-        Deprecated: use for_room_version with a RoomVersion object instead
-
-        Args:
-            room_version: Version of the room that we're creating an event builder for
-            key_values: Fields used as the basis of the new event
-
-        Returns:
-            EventBuilder
-        """
-        v = KNOWN_ROOM_VERSIONS.get(room_version)
-        if not v:
-            # this can happen if support is withdrawn for a room version
-            raise UnsupportedRoomVersionError()
-        return self.for_room_version(v, key_values)
-
     def for_room_version(
         self, room_version: RoomVersion, key_values: dict
     ) -> EventBuilder:
diff --git a/synapse/events/presence_router.py b/synapse/events/presence_router.py
index eb4556cdc1..68b8b19024 100644
--- a/synapse/events/presence_router.py
+++ b/synapse/events/presence_router.py
@@ -45,11 +45,11 @@ def load_legacy_presence_router(hs: "HomeServer"):
     configuration, and registers the hooks they implement.
     """
 
-    if hs.config.presence_router_module_class is None:
+    if hs.config.server.presence_router_module_class is None:
         return
 
-    module = hs.config.presence_router_module_class
-    config = hs.config.presence_router_config
+    module = hs.config.server.presence_router_module_class
+    config = hs.config.server.presence_router_config
     api = hs.get_module_api()
 
     presence_router = module(config=config, module_api=api)
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 38fccd1efc..520edbbf61 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -372,7 +372,7 @@ class EventClientSerializer:
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.experimental_msc1849_support_enabled = (
-            hs.config.experimental_msc1849_support_enabled
+            hs.config.server.experimental_msc1849_support_enabled
         )
 
     async def serialize_event(
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 5f4383eebc..d8c0b86f23 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -1008,7 +1008,10 @@ class FederationServer(FederationBase):
             async with lock:
                 logger.info("handling received PDU: %s", event)
                 try:
-                    await self._federation_event_handler.on_receive_pdu(origin, event)
+                    with nested_logging_context(event.event_id):
+                        await self._federation_event_handler.on_receive_pdu(
+                            origin, event
+                        )
                 except FederationError as e:
                     # XXX: Ideally we'd inform the remote we failed to process
                     # the event, but we can't return an error in the transaction
diff --git a/synapse/federation/transport/server/__init__.py b/synapse/federation/transport/server/__init__.py
index 95176ba6f9..c32539bf5a 100644
--- a/synapse/federation/transport/server/__init__.py
+++ b/synapse/federation/transport/server/__init__.py
@@ -117,7 +117,7 @@ class PublicRoomList(BaseFederationServlet):
     ):
         super().__init__(hs, authenticator, ratelimiter, server_name)
         self.handler = hs.get_room_list_handler()
-        self.allow_access = hs.config.allow_public_rooms_over_federation
+        self.allow_access = hs.config.server.allow_public_rooms_over_federation
 
     async def on_GET(
         self, origin: str, content: Literal[None], query: Dict[bytes, List[bytes]]
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index a8c717efd5..2d0f3d566c 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -198,7 +198,7 @@ class AuthHandler(BaseHandler):
             if inst.is_enabled():
                 self.checkers[inst.AUTH_TYPE] = inst  # type: ignore
 
-        self.bcrypt_rounds = hs.config.bcrypt_rounds
+        self.bcrypt_rounds = hs.config.registration.bcrypt_rounds
 
         # we can't use hs.get_module_api() here, because to do so will create an
         # import loop.
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 9ae5b7750e..12bdca7445 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -133,6 +133,10 @@ class DeactivateAccountHandler(BaseHandler):
         # delete from user directory
         await self.user_directory_handler.handle_local_user_deactivated(user_id)
 
+        # If the user is present in the monthly active users table
+        # remove them
+        await self.store.remove_deactivated_user_from_mau_table(user_id)
+
         # Mark the user as erased, if they asked for that
         if erase_data:
             user = UserID.from_string(user_id)
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 5cfba3c817..9078781d5a 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -49,7 +49,7 @@ class DirectoryHandler(BaseHandler):
         self.store = hs.get_datastore()
         self.config = hs.config
         self.enable_room_list_search = hs.config.roomdirectory.enable_room_list_search
-        self.require_membership = hs.config.require_membership_for_aliases
+        self.require_membership = hs.config.server.require_membership_for_aliases
         self.third_party_event_rules = hs.get_third_party_event_rules()
 
         self.federation = hs.get_federation_client()
diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py
index cb81fa0986..d089c56286 100644
--- a/synapse/handlers/event_auth.py
+++ b/synapse/handlers/event_auth.py
@@ -22,7 +22,8 @@ from synapse.api.constants import (
     RestrictedJoinRuleTypes,
 )
 from synapse.api.errors import AuthError, Codes, SynapseError
-from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
+from synapse.api.room_versions import RoomVersion
+from synapse.event_auth import check_auth_rules_for_event
 from synapse.events import EventBase
 from synapse.events.builder import EventBuilder
 from synapse.events.snapshot import EventContext
@@ -45,21 +46,17 @@ class EventAuthHandler:
         self._store = hs.get_datastore()
         self._server_name = hs.hostname
 
-    async def check_from_context(
+    async def check_auth_rules_from_context(
         self,
-        room_version: str,
+        room_version_obj: RoomVersion,
         event: EventBase,
         context: EventContext,
-        do_sig_check: bool = True,
     ) -> None:
+        """Check an event passes the auth rules at its own auth events"""
         auth_event_ids = event.auth_event_ids()
         auth_events_by_id = await self._store.get_events(auth_event_ids)
         auth_events = {(e.type, e.state_key): e for e in auth_events_by_id.values()}
-
-        room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
-        event_auth.check(
-            room_version_obj, event, auth_events=auth_events, do_sig_check=do_sig_check
-        )
+        check_auth_rules_for_event(room_version_obj, event, auth_events)
 
     def compute_auth_events(
         self,
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index adbd150e46..043ca4a224 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -45,6 +45,10 @@ from synapse.api.errors import (
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion, RoomVersions
 from synapse.crypto.event_signing import compute_event_signature
+from synapse.event_auth import (
+    check_auth_rules_for_event,
+    validate_event_for_room_version,
+)
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.events.validator import EventValidator
@@ -723,8 +727,8 @@ class FederationHandler(BaseHandler):
                         state_ids,
                     )
 
-        builder = self.event_builder_factory.new(
-            room_version.identifier,
+        builder = self.event_builder_factory.for_room_version(
+            room_version,
             {
                 "type": EventTypes.Member,
                 "content": event_content,
@@ -747,10 +751,9 @@ class FederationHandler(BaseHandler):
 
         # The remote hasn't signed it yet, obviously. We'll do the full checks
         # when we get the event back in `on_send_join_request`
-        await self._event_auth_handler.check_from_context(
-            room_version.identifier, event, context, do_sig_check=False
+        await self._event_auth_handler.check_auth_rules_from_context(
+            room_version, event, context
         )
-
         return event
 
     async def on_invite_request(
@@ -767,7 +770,7 @@ class FederationHandler(BaseHandler):
         if is_blocked:
             raise SynapseError(403, "This room has been blocked on this server")
 
-        if self.hs.config.block_non_admin_invites:
+        if self.hs.config.server.block_non_admin_invites:
             raise SynapseError(403, "This server does not accept room invites")
 
         if not await self.spam_checker.user_may_invite(
@@ -902,9 +905,9 @@ class FederationHandler(BaseHandler):
             )
             raise SynapseError(403, "User not from origin", Codes.FORBIDDEN)
 
-        room_version = await self.store.get_room_version_id(room_id)
-        builder = self.event_builder_factory.new(
-            room_version,
+        room_version_obj = await self.store.get_room_version(room_id)
+        builder = self.event_builder_factory.for_room_version(
+            room_version_obj,
             {
                 "type": EventTypes.Member,
                 "content": {"membership": Membership.LEAVE},
@@ -921,8 +924,8 @@ class FederationHandler(BaseHandler):
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_leave_request`
-            await self._event_auth_handler.check_from_context(
-                room_version, event, context, do_sig_check=False
+            await self._event_auth_handler.check_auth_rules_from_context(
+                room_version_obj, event, context
             )
         except AuthError as e:
             logger.warning("Failed to create new leave %r because %s", event, e)
@@ -954,10 +957,10 @@ class FederationHandler(BaseHandler):
             )
             raise SynapseError(403, "User not from origin", Codes.FORBIDDEN)
 
-        room_version = await self.store.get_room_version_id(room_id)
+        room_version_obj = await self.store.get_room_version(room_id)
 
-        builder = self.event_builder_factory.new(
-            room_version,
+        builder = self.event_builder_factory.for_room_version(
+            room_version_obj,
             {
                 "type": EventTypes.Member,
                 "content": {"membership": Membership.KNOCK},
@@ -983,8 +986,8 @@ class FederationHandler(BaseHandler):
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_knock_request`
-            await self._event_auth_handler.check_from_context(
-                room_version, event, context, do_sig_check=False
+            await self._event_auth_handler.check_auth_rules_from_context(
+                room_version_obj, event, context
             )
         except AuthError as e:
             logger.warning("Failed to create new knock %r because %s", event, e)
@@ -1173,7 +1176,8 @@ class FederationHandler(BaseHandler):
                 auth_for_e[(EventTypes.Create, "")] = create_event
 
             try:
-                event_auth.check(room_version, e, auth_events=auth_for_e)
+                validate_event_for_room_version(room_version, e)
+                check_auth_rules_for_event(room_version, e, auth_for_e)
             except SynapseError as err:
                 # we may get SynapseErrors here as well as AuthErrors. For
                 # instance, there are a couple of (ancient) events in some
@@ -1250,8 +1254,10 @@ class FederationHandler(BaseHandler):
         }
 
         if await self._event_auth_handler.check_host_in_room(room_id, self.hs.hostname):
-            room_version = await self.store.get_room_version_id(room_id)
-            builder = self.event_builder_factory.new(room_version, event_dict)
+            room_version_obj = await self.store.get_room_version(room_id)
+            builder = self.event_builder_factory.for_room_version(
+                room_version_obj, event_dict
+            )
 
             EventValidator().validate_builder(builder)
             event, context = await self.event_creation_handler.create_new_client_event(
@@ -1259,7 +1265,7 @@ class FederationHandler(BaseHandler):
             )
 
             event, context = await self.add_display_name_to_third_party_invite(
-                room_version, event_dict, event, context
+                room_version_obj, event_dict, event, context
             )
 
             EventValidator().validate_new(event, self.config)
@@ -1269,8 +1275,9 @@ class FederationHandler(BaseHandler):
             event.internal_metadata.send_on_behalf_of = self.hs.hostname
 
             try:
-                await self._event_auth_handler.check_from_context(
-                    room_version, event, context
+                validate_event_for_room_version(room_version_obj, event)
+                await self._event_auth_handler.check_auth_rules_from_context(
+                    room_version_obj, event, context
                 )
             except AuthError as e:
                 logger.warning("Denying new third party invite %r because %s", event, e)
@@ -1304,22 +1311,25 @@ class FederationHandler(BaseHandler):
 
         """
         assert_params_in_dict(event_dict, ["room_id"])
-        room_version = await self.store.get_room_version_id(event_dict["room_id"])
+        room_version_obj = await self.store.get_room_version(event_dict["room_id"])
 
         # NB: event_dict has a particular specced format we might need to fudge
         # if we change event formats too much.
-        builder = self.event_builder_factory.new(room_version, event_dict)
+        builder = self.event_builder_factory.for_room_version(
+            room_version_obj, event_dict
+        )
 
         event, context = await self.event_creation_handler.create_new_client_event(
             builder=builder
         )
         event, context = await self.add_display_name_to_third_party_invite(
-            room_version, event_dict, event, context
+            room_version_obj, event_dict, event, context
         )
 
         try:
-            await self._event_auth_handler.check_from_context(
-                room_version, event, context
+            validate_event_for_room_version(room_version_obj, event)
+            await self._event_auth_handler.check_auth_rules_from_context(
+                room_version_obj, event, context
             )
         except AuthError as e:
             logger.warning("Denying third party invite %r because %s", event, e)
@@ -1336,7 +1346,7 @@ class FederationHandler(BaseHandler):
 
     async def add_display_name_to_third_party_invite(
         self,
-        room_version: str,
+        room_version_obj: RoomVersion,
         event_dict: JsonDict,
         event: EventBase,
         context: EventContext,
@@ -1368,7 +1378,9 @@ class FederationHandler(BaseHandler):
             # auth checks. If we need the invite and don't have it then the
             # auth check code will explode appropriately.
 
-        builder = self.event_builder_factory.new(room_version, event_dict)
+        builder = self.event_builder_factory.for_room_version(
+            room_version_obj, event_dict
+        )
         EventValidator().validate_builder(builder)
         event, context = await self.event_creation_handler.create_new_client_event(
             builder=builder
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 01fd841122..9269cb444d 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -29,7 +29,6 @@ from typing import (
 
 from prometheus_client import Counter
 
-from synapse import event_auth
 from synapse.api.constants import (
     EventContentFields,
     EventTypes,
@@ -47,7 +46,11 @@ from synapse.api.errors import (
     SynapseError,
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
-from synapse.event_auth import auth_types_for_event
+from synapse.event_auth import (
+    auth_types_for_event,
+    check_auth_rules_for_event,
+    validate_event_for_room_version,
+)
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.federation.federation_client import InvalidResponseError
@@ -68,11 +71,7 @@ from synapse.types import (
     UserID,
     get_domain_from_id,
 )
-from synapse.util.async_helpers import (
-    Linearizer,
-    concurrently_execute,
-    yieldable_gather_results,
-)
+from synapse.util.async_helpers import Linearizer, concurrently_execute
 from synapse.util.iterutils import batch_iter
 from synapse.util.retryutils import NotRetryingDestination
 from synapse.util.stringutils import shortstr
@@ -357,6 +356,11 @@ class FederationEventHandler:
                 )
 
         # all looks good, we can persist the event.
+
+        # First, precalculate the joined hosts so that the federation sender doesn't
+        # need to.
+        await self._event_creation_handler.cache_joined_hosts_for_event(event, context)
+
         await self._run_push_actions_and_persist_event(event, context)
         return event, context
 
@@ -1189,7 +1193,10 @@ class FederationEventHandler:
             allow_rejected=True,
         )
 
-        async def prep(event: EventBase) -> Optional[Tuple[EventBase, EventContext]]:
+        room_version = await self._store.get_room_version_id(room_id)
+        room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
+
+        def prep(event: EventBase) -> Optional[Tuple[EventBase, EventContext]]:
             with nested_logging_context(suffix=event.event_id):
                 auth = {}
                 for auth_event_id in event.auth_event_ids():
@@ -1207,17 +1214,16 @@ class FederationEventHandler:
                     auth[(ae.type, ae.state_key)] = ae
 
                 context = EventContext.for_outlier()
-                context = await self._check_event_auth(
-                    origin,
-                    event,
-                    context,
-                    claimed_auth_event_map=auth,
-                )
+                try:
+                    validate_event_for_room_version(room_version_obj, event)
+                    check_auth_rules_for_event(room_version_obj, event, auth)
+                except AuthError as e:
+                    logger.warning("Rejecting %r because %s", event, e)
+                    context.rejected = RejectedReason.AUTH_ERROR
+
             return event, context
 
-        events_to_persist = (
-            x for x in await yieldable_gather_results(prep, fetched_events) if x
-        )
+        events_to_persist = (x for x in (prep(event) for event in fetched_events) if x)
         await self.persist_events_and_notify(room_id, tuple(events_to_persist))
 
     async def _check_event_auth(
@@ -1226,7 +1232,6 @@ class FederationEventHandler:
         event: EventBase,
         context: EventContext,
         state: Optional[Iterable[EventBase]] = None,
-        claimed_auth_event_map: Optional[StateMap[EventBase]] = None,
         backfilled: bool = False,
     ) -> EventContext:
         """
@@ -1242,42 +1247,45 @@ class FederationEventHandler:
                 The state events used to check the event for soft-fail. If this is
                 not provided the current state events will be used.
 
-            claimed_auth_event_map:
-                A map of (type, state_key) => event for the event's claimed auth_events.
-                Possibly including events that were rejected, or are in the wrong room.
-
-                Only populated when populating outliers.
-
             backfilled: True if the event was backfilled.
 
         Returns:
             The updated context object.
         """
-        # claimed_auth_event_map should be given iff the event is an outlier
-        assert bool(claimed_auth_event_map) == event.internal_metadata.outlier
+        # This method should only be used for non-outliers
+        assert not event.internal_metadata.outlier
 
+        # first of all, check that the event itself is valid.
         room_version = await self._store.get_room_version_id(event.room_id)
         room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
 
-        if claimed_auth_event_map:
-            # if we have a copy of the auth events from the event, use that as the
-            # basis for auth.
-            auth_events = claimed_auth_event_map
-        else:
-            # otherwise, we calculate what the auth events *should* be, and use that
-            prev_state_ids = await context.get_prev_state_ids()
-            auth_events_ids = self._event_auth_handler.compute_auth_events(
-                event, prev_state_ids, for_verification=True
-            )
-            auth_events_x = await self._store.get_events(auth_events_ids)
-            auth_events = {(e.type, e.state_key): e for e in auth_events_x.values()}
+        try:
+            validate_event_for_room_version(room_version_obj, event)
+        except AuthError as e:
+            logger.warning("While validating received event %r: %s", event, e)
+            # TODO: use a different rejected reason here?
+            context.rejected = RejectedReason.AUTH_ERROR
+            return context
+
+        # calculate what the auth events *should* be, to use as a basis for auth.
+        prev_state_ids = await context.get_prev_state_ids()
+        auth_events_ids = self._event_auth_handler.compute_auth_events(
+            event, prev_state_ids, for_verification=True
+        )
+        auth_events_x = await self._store.get_events(auth_events_ids)
+        calculated_auth_event_map = {
+            (e.type, e.state_key): e for e in auth_events_x.values()
+        }
 
         try:
             (
                 context,
                 auth_events_for_auth,
             ) = await self._update_auth_events_and_context_for_auth(
-                origin, event, context, auth_events
+                origin,
+                event,
+                context,
+                calculated_auth_event_map=calculated_auth_event_map,
             )
         except Exception:
             # We don't really mind if the above fails, so lets not fail
@@ -1289,24 +1297,17 @@ class FederationEventHandler:
                 "Ignoring failure and continuing processing of event.",
                 event.event_id,
             )
-            auth_events_for_auth = auth_events
+            auth_events_for_auth = calculated_auth_event_map
 
         try:
-            event_auth.check(room_version_obj, event, auth_events=auth_events_for_auth)
+            check_auth_rules_for_event(room_version_obj, event, auth_events_for_auth)
         except AuthError as e:
             logger.warning("Failed auth resolution for %r because %s", event, e)
             context.rejected = RejectedReason.AUTH_ERROR
+            return context
 
-        if not context.rejected:
-            await self._check_for_soft_fail(event, state, backfilled, origin=origin)
-            await self._maybe_kick_guest_users(event)
-
-        # If we are going to send this event over federation we precaclculate
-        # the joined hosts.
-        if event.internal_metadata.get_send_on_behalf_of():
-            await self._event_creation_handler.cache_joined_hosts_for_event(
-                event, context
-            )
+        await self._check_for_soft_fail(event, state, backfilled, origin=origin)
+        await self._maybe_kick_guest_users(event)
 
         return context
 
@@ -1404,7 +1405,7 @@ class FederationEventHandler:
         }
 
         try:
-            event_auth.check(room_version_obj, event, auth_events=current_auth_events)
+            check_auth_rules_for_event(room_version_obj, event, current_auth_events)
         except AuthError as e:
             logger.warning(
                 "Soft-failing %r (from %s) because %s",
@@ -1425,7 +1426,7 @@ class FederationEventHandler:
         origin: str,
         event: EventBase,
         context: EventContext,
-        input_auth_events: StateMap[EventBase],
+        calculated_auth_event_map: StateMap[EventBase],
     ) -> Tuple[EventContext, StateMap[EventBase]]:
         """Helper for _check_event_auth. See there for docs.
 
@@ -1443,19 +1444,17 @@ class FederationEventHandler:
             event:
             context:
 
-            input_auth_events:
-                Map from (event_type, state_key) to event
-
-                Normally, our calculated auth_events based on the state of the room
-                at the event's position in the DAG, though occasionally (eg if the
-                event is an outlier), may be the auth events claimed by the remote
-                server.
+            calculated_auth_event_map:
+                Our calculated auth_events based on the state of the room
+                at the event's position in the DAG.
 
         Returns:
             updated context, updated auth event map
         """
-        # take a copy of input_auth_events before we modify it.
-        auth_events: MutableStateMap[EventBase] = dict(input_auth_events)
+        assert not event.internal_metadata.outlier
+
+        # take a copy of calculated_auth_event_map before we modify it.
+        auth_events: MutableStateMap[EventBase] = dict(calculated_auth_event_map)
 
         event_auth_events = set(event.auth_event_ids())
 
@@ -1475,6 +1474,11 @@ class FederationEventHandler:
             logger.debug("Events %s are in the store", have_events)
             missing_auth.difference_update(have_events)
 
+        # missing_auth is now the set of event_ids which:
+        #  a. are listed in event.auth_events, *and*
+        #  b. are *not* part of our calculated auth events based on room state, *and*
+        #  c. are *not* yet in our database.
+
         if missing_auth:
             # If we don't have all the auth events, we need to get them.
             logger.info("auth_events contains unknown events: %s", missing_auth)
@@ -1496,19 +1500,31 @@ class FederationEventHandler:
                     }
                 )
 
-        if event.internal_metadata.is_outlier():
-            # XXX: given that, for an outlier, we'll be working with the
-            # event's *claimed* auth events rather than those we calculated:
-            # (a) is there any point in this test, since different_auth below will
-            # obviously be empty
-            # (b) alternatively, why don't we do it earlier?
-            logger.info("Skipping auth_event fetch for outlier")
-            return context, auth_events
+        # auth_events now contains
+        #   1. our *calculated* auth events based on the room state, plus:
+        #   2. any events which:
+        #       a. are listed in `event.auth_events`, *and*
+        #       b. are not part of our calculated auth events, *and*
+        #       c. were not in our database before the call to /event_auth
+        #       d. have since been added to our database (most likely by /event_auth).
 
         different_auth = event_auth_events.difference(
             e.event_id for e in auth_events.values()
         )
 
+        # different_auth is the set of events which *are* in `event.auth_events`, but
+        # which are *not* in `auth_events`. Comparing with (2.) above, this means
+        # exclusively the set of `event.auth_events` which we already had in our
+        # database before any call to /event_auth.
+        #
+        # I'm reasonably sure that the fact that events returned by /event_auth are
+        # blindly added to auth_events (and hence excluded from different_auth) is a bug
+        # - though it's a very long-standing one (see
+        # https://github.com/matrix-org/synapse/commit/78015948a7febb18e000651f72f8f58830a55b93#diff-0bc92da3d703202f5b9be2d3f845e375f5b1a6bc6ba61705a8af9be1121f5e42R786
+        # from Jan 2015 which seems to add it, though it actually just moves it from
+        # elsewhere (before that, it gets lost in a mess of huge "various bug fixes"
+        # PRs).
+
         if not different_auth:
             return context, auth_events
 
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index fe8a995892..c881475c25 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -57,7 +57,7 @@ class IdentityHandler(BaseHandler):
         self.http_client = SimpleHttpClient(hs)
         # An HTTP client for contacting identity servers specified by clients.
         self.blacklisting_http_client = SimpleHttpClient(
-            hs, ip_blacklist=hs.config.federation_ip_range_blacklist
+            hs, ip_blacklist=hs.config.server.federation_ip_range_blacklist
         )
         self.federation_http_client = hs.get_federation_http_client()
         self.hs = hs
@@ -573,9 +573,15 @@ class IdentityHandler(BaseHandler):
 
         # Try to validate as email
         if self.hs.config.email.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
+            # Remote emails will only be used if a valid identity server is provided.
+            assert (
+                self.hs.config.registration.account_threepid_delegate_email is not None
+            )
+
             # Ask our delegated email identity server
             validation_session = await self.threepid_from_creds(
-                self.hs.config.account_threepid_delegate_email, threepid_creds
+                self.hs.config.registration.account_threepid_delegate_email,
+                threepid_creds,
             )
         elif self.hs.config.email.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
             # Get a validated session matching these details
@@ -587,10 +593,11 @@ class IdentityHandler(BaseHandler):
             return validation_session
 
         # Try to validate as msisdn
-        if self.hs.config.account_threepid_delegate_msisdn:
+        if self.hs.config.registration.account_threepid_delegate_msisdn:
             # Ask our delegated msisdn identity server
             validation_session = await self.threepid_from_creds(
-                self.hs.config.account_threepid_delegate_msisdn, threepid_creds
+                self.hs.config.registration.account_threepid_delegate_msisdn,
+                threepid_creds,
             )
 
         return validation_session
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index fd861e94f8..ccd7827207 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -16,6 +16,7 @@
 # limitations under the License.
 import logging
 import random
+from http import HTTPStatus
 from typing import TYPE_CHECKING, Any, Dict, List, Mapping, Optional, Tuple
 
 from canonicaljson import encode_canonical_json
@@ -39,9 +40,11 @@ from synapse.api.errors import (
     NotFoundError,
     ShadowBanError,
     SynapseError,
+    UnsupportedRoomVersionError,
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
 from synapse.api.urls import ConsentURIBuilder
+from synapse.event_auth import validate_event_for_room_version
 from synapse.events import EventBase
 from synapse.events.builder import EventBuilder
 from synapse.events.snapshot import EventContext
@@ -79,7 +82,7 @@ class MessageHandler:
         self.storage = hs.get_storage()
         self.state_store = self.storage.state
         self._event_serializer = hs.get_event_client_serializer()
-        self._ephemeral_events_enabled = hs.config.enable_ephemeral_messages
+        self._ephemeral_events_enabled = hs.config.server.enable_ephemeral_messages
 
         # The scheduled call to self._expire_event. None if no call is currently
         # scheduled.
@@ -413,7 +416,9 @@ class EventCreationHandler:
         self.server_name = hs.hostname
         self.notifier = hs.get_notifier()
         self.config = hs.config
-        self.require_membership_for_aliases = hs.config.require_membership_for_aliases
+        self.require_membership_for_aliases = (
+            hs.config.server.require_membership_for_aliases
+        )
         self._events_shard_config = self.config.worker.events_shard_config
         self._instance_name = hs.get_instance_name()
 
@@ -423,7 +428,7 @@ class EventCreationHandler:
             Membership.JOIN,
             Membership.KNOCK,
         }
-        if self.hs.config.include_profile_data_on_invite:
+        if self.hs.config.server.include_profile_data_on_invite:
             self.membership_types_to_include_profile_data_in.add(Membership.INVITE)
 
         self.send_event = ReplicationSendEventRestServlet.make_client(hs)
@@ -459,11 +464,11 @@ class EventCreationHandler:
         #
         self._rooms_to_exclude_from_dummy_event_insertion: Dict[str, int] = {}
         # The number of forward extremeities before a dummy event is sent.
-        self._dummy_events_threshold = hs.config.dummy_events_threshold
+        self._dummy_events_threshold = hs.config.server.dummy_events_threshold
 
         if (
             self.config.worker.run_background_tasks
-            and self.config.cleanup_extremities_with_dummy_events
+            and self.config.server.cleanup_extremities_with_dummy_events
         ):
             self.clock.looping_call(
                 lambda: run_as_background_process(
@@ -475,7 +480,7 @@ class EventCreationHandler:
 
         self._message_handler = hs.get_message_handler()
 
-        self._ephemeral_events_enabled = hs.config.enable_ephemeral_messages
+        self._ephemeral_events_enabled = hs.config.server.enable_ephemeral_messages
 
         self._external_cache = hs.get_external_cache()
 
@@ -549,16 +554,22 @@ class EventCreationHandler:
         await self.auth.check_auth_blocking(requester=requester)
 
         if event_dict["type"] == EventTypes.Create and event_dict["state_key"] == "":
-            room_version = event_dict["content"]["room_version"]
+            room_version_id = event_dict["content"]["room_version"]
+            room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version_id)
+            if not room_version_obj:
+                # this can happen if support is withdrawn for a room version
+                raise UnsupportedRoomVersionError(room_version_id)
         else:
             try:
-                room_version = await self.store.get_room_version_id(
+                room_version_obj = await self.store.get_room_version(
                     event_dict["room_id"]
                 )
             except NotFoundError:
                 raise AuthError(403, "Unknown room")
 
-        builder = self.event_builder_factory.new(room_version, event_dict)
+        builder = self.event_builder_factory.for_room_version(
+            room_version_obj, event_dict
+        )
 
         self.validator.validate_builder(builder)
 
@@ -1064,9 +1075,17 @@ class EventCreationHandler:
             EventTypes.Create,
             "",
         ):
-            room_version = event.content.get("room_version", RoomVersions.V1.identifier)
+            room_version_id = event.content.get(
+                "room_version", RoomVersions.V1.identifier
+            )
+            room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version_id)
+            if not room_version_obj:
+                raise UnsupportedRoomVersionError(
+                    "Attempt to create a room with unsupported room version %s"
+                    % (room_version_id,)
+                )
         else:
-            room_version = await self.store.get_room_version_id(event.room_id)
+            room_version_obj = await self.store.get_room_version(event.room_id)
 
         if event.internal_metadata.is_out_of_band_membership():
             # the only sort of out-of-band-membership events we expect to see here are
@@ -1075,8 +1094,9 @@ class EventCreationHandler:
             assert event.content["membership"] == Membership.LEAVE
         else:
             try:
-                await self._event_auth_handler.check_from_context(
-                    room_version, event, context
+                validate_event_for_room_version(room_version_obj, event)
+                await self._event_auth_handler.check_auth_rules_from_context(
+                    room_version_obj, event, context
                 )
             except AuthError as err:
                 logger.warning("Denying new event %r because %s", event, err)
@@ -1456,6 +1476,39 @@ class EventCreationHandler:
             if prev_state_ids:
                 raise AuthError(403, "Changing the room create event is forbidden")
 
+        if event.type == EventTypes.MSC2716_INSERTION:
+            room_version = await self.store.get_room_version_id(event.room_id)
+            room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
+
+            create_event = await self.store.get_create_event_for_room(event.room_id)
+            room_creator = create_event.content.get(EventContentFields.ROOM_CREATOR)
+
+            # Only check an insertion event if the room version
+            # supports it or the event is from the room creator.
+            if room_version_obj.msc2716_historical or (
+                self.config.experimental.msc2716_enabled
+                and event.sender == room_creator
+            ):
+                next_batch_id = event.content.get(
+                    EventContentFields.MSC2716_NEXT_BATCH_ID
+                )
+                conflicting_insertion_event_id = (
+                    await self.store.get_insertion_event_by_batch_id(
+                        event.room_id, next_batch_id
+                    )
+                )
+                if conflicting_insertion_event_id is not None:
+                    # The current insertion event that we're processing is invalid
+                    # because an insertion event already exists in the room with the
+                    # same next_batch_id. We can't allow multiple because the batch
+                    # pointing will get weird, e.g. we can't determine which insertion
+                    # event the batch event is pointing to.
+                    raise SynapseError(
+                        HTTPStatus.BAD_REQUEST,
+                        "Another insertion event already exists with the same next_batch_id",
+                        errcode=Codes.INVALID_PARAM,
+                    )
+
         # Mark any `m.historical` messages as backfilled so they don't appear
         # in `/sync` and have the proper decrementing `stream_ordering` as we import
         backfilled = False
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 08b93b3ec1..176e4dfdd4 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -85,23 +85,29 @@ class PaginationHandler:
         self._purges_by_id: Dict[str, PurgeStatus] = {}
         self._event_serializer = hs.get_event_client_serializer()
 
-        self._retention_default_max_lifetime = hs.config.retention_default_max_lifetime
+        self._retention_default_max_lifetime = (
+            hs.config.server.retention_default_max_lifetime
+        )
 
-        self._retention_allowed_lifetime_min = hs.config.retention_allowed_lifetime_min
-        self._retention_allowed_lifetime_max = hs.config.retention_allowed_lifetime_max
+        self._retention_allowed_lifetime_min = (
+            hs.config.server.retention_allowed_lifetime_min
+        )
+        self._retention_allowed_lifetime_max = (
+            hs.config.server.retention_allowed_lifetime_max
+        )
 
-        if hs.config.worker.run_background_tasks and hs.config.retention_enabled:
+        if hs.config.worker.run_background_tasks and hs.config.server.retention_enabled:
             # Run the purge jobs described in the configuration file.
-            for job in hs.config.retention_purge_jobs:
+            for job in hs.config.server.retention_purge_jobs:
                 logger.info("Setting up purge job with config: %s", job)
 
                 self.clock.looping_call(
                     run_as_background_process,
-                    job["interval"],
+                    job.interval,
                     "purge_history_for_rooms_in_range",
                     self.purge_history_for_rooms_in_range,
-                    job["shortest_max_lifetime"],
-                    job["longest_max_lifetime"],
+                    job.shortest_max_lifetime,
+                    job.longest_max_lifetime,
                 )
 
     async def purge_history_for_rooms_in_range(
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index b23a1541bc..2e19706c69 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -178,7 +178,7 @@ class ProfileHandler(BaseHandler):
         if not by_admin and target_user != requester.user:
             raise AuthError(400, "Cannot set another user's displayname")
 
-        if not by_admin and not self.hs.config.enable_set_displayname:
+        if not by_admin and not self.hs.config.registration.enable_set_displayname:
             profile = await self.store.get_profileinfo(target_user.localpart)
             if profile.display_name:
                 raise SynapseError(
@@ -268,7 +268,7 @@ class ProfileHandler(BaseHandler):
         if not by_admin and target_user != requester.user:
             raise AuthError(400, "Cannot set another user's avatar_url")
 
-        if not by_admin and not self.hs.config.enable_set_avatar_url:
+        if not by_admin and not self.hs.config.registration.enable_set_avatar_url:
             profile = await self.store.get_profileinfo(target_user.localpart)
             if profile.avatar_url:
                 raise SynapseError(
@@ -397,7 +397,7 @@ class ProfileHandler(BaseHandler):
         # when building a membership event. In this case, we must allow the
         # lookup.
         if (
-            not self.hs.config.limit_profile_requests_to_users_who_share_rooms
+            not self.hs.config.server.limit_profile_requests_to_users_who_share_rooms
             or not requester
         ):
             return
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 4f99f137a2..441af7a848 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -116,8 +116,8 @@ class RegistrationHandler(BaseHandler):
             self._register_device_client = self.register_device_inner
             self.pusher_pool = hs.get_pusherpool()
 
-        self.session_lifetime = hs.config.session_lifetime
-        self.access_token_lifetime = hs.config.access_token_lifetime
+        self.session_lifetime = hs.config.registration.session_lifetime
+        self.access_token_lifetime = hs.config.registration.access_token_lifetime
 
         init_counters_for_auth_provider("")
 
@@ -340,8 +340,13 @@ class RegistrationHandler(BaseHandler):
             auth_provider=(auth_provider_id or ""),
         ).inc()
 
+        # If the user does not need to consent at registration, auto-join any
+        # configured rooms.
         if not self.hs.config.consent.user_consent_at_registration:
-            if not self.hs.config.auto_join_rooms_for_guests and make_guest:
+            if (
+                not self.hs.config.registration.auto_join_rooms_for_guests
+                and make_guest
+            ):
                 logger.info(
                     "Skipping auto-join for %s because auto-join for guests is disabled",
                     user_id,
@@ -387,7 +392,7 @@ class RegistrationHandler(BaseHandler):
             "preset": self.hs.config.registration.autocreate_auto_join_room_preset,
         }
 
-        # If the configuration providers a user ID to create rooms with, use
+        # If the configuration provides a user ID to create rooms with, use
         # that instead of the first user registered.
         requires_join = False
         if self.hs.config.registration.auto_join_user_id:
@@ -854,7 +859,7 @@ class RegistrationHandler(BaseHandler):
             # Necessary due to auth checks prior to the threepid being
             # written to the db
             if is_threepid_reserved(
-                self.hs.config.mau_limits_reserved_threepids, threepid
+                self.hs.config.server.mau_limits_reserved_threepids, threepid
             ):
                 await self.store.upsert_monthly_active_user(user_id)
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 8fede5e935..873e08258e 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -52,6 +52,7 @@ from synapse.api.errors import (
 )
 from synapse.api.filtering import Filter
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
+from synapse.event_auth import validate_event_for_room_version
 from synapse.events import EventBase
 from synapse.events.utils import copy_power_levels_contents
 from synapse.rest.admin._base import assert_user_is_admin
@@ -237,8 +238,9 @@ class RoomCreationHandler(BaseHandler):
                 },
             },
         )
-        old_room_version = await self.store.get_room_version_id(old_room_id)
-        await self._event_auth_handler.check_from_context(
+        old_room_version = await self.store.get_room_version(old_room_id)
+        validate_event_for_room_version(old_room_version, tombstone_event)
+        await self._event_auth_handler.check_auth_rules_from_context(
             old_room_version, tombstone_event, tombstone_context
         )
 
@@ -666,7 +668,7 @@ class RoomCreationHandler(BaseHandler):
             await self.ratelimit(requester)
 
         room_version_id = config.get(
-            "room_version", self.config.default_room_version.identifier
+            "room_version", self.config.server.default_room_version.identifier
         )
 
         if not isinstance(room_version_id, str):
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index afa7e4727d..c8fb24a20c 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -89,8 +89,8 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         self.spam_checker = hs.get_spam_checker()
         self.third_party_event_rules = hs.get_third_party_event_rules()
         self._server_notices_mxid = self.config.servernotices.server_notices_mxid
-        self._enable_lookup = hs.config.enable_3pid_lookup
-        self.allow_per_room_profiles = self.config.allow_per_room_profiles
+        self._enable_lookup = hs.config.registration.enable_3pid_lookup
+        self.allow_per_room_profiles = self.config.server.allow_per_room_profiles
 
         self._join_rate_limiter_local = Ratelimiter(
             store=self.store,
@@ -625,7 +625,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                 is_requester_admin = await self.auth.is_server_admin(requester.user)
 
             if not is_requester_admin:
-                if self.config.block_non_admin_invites:
+                if self.config.server.block_non_admin_invites:
                     logger.info(
                         "Blocking invite: user is not admin and non-admin "
                         "invites disabled"
@@ -1230,7 +1230,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         Raises:
             ShadowBanError if the requester has been shadow-banned.
         """
-        if self.config.block_non_admin_invites:
+        if self.config.server.block_non_admin_invites:
             is_requester_admin = await self.auth.is_server_admin(requester.user)
             if not is_requester_admin:
                 raise SynapseError(
@@ -1428,7 +1428,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         Returns: bool of whether the complexity is too great, or None
             if unable to be fetched
         """
-        max_complexity = self.hs.config.limit_remote_rooms.complexity
+        max_complexity = self.hs.config.server.limit_remote_rooms.complexity
         complexity = await self.federation_handler.get_room_complexity(
             remote_room_hosts, room_id
         )
@@ -1444,7 +1444,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         Args:
             room_id: The room ID to check for complexity.
         """
-        max_complexity = self.hs.config.limit_remote_rooms.complexity
+        max_complexity = self.hs.config.server.limit_remote_rooms.complexity
         complexity = await self.store.get_room_complexity(room_id)
 
         return complexity["v1"] > max_complexity
@@ -1480,7 +1480,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             if too_complex is True:
                 raise SynapseError(
                     code=400,
-                    msg=self.hs.config.limit_remote_rooms.complexity_error,
+                    msg=self.hs.config.server.limit_remote_rooms.complexity_error,
                     errcode=Codes.RESOURCE_LIMIT_EXCEEDED,
                 )
 
@@ -1515,7 +1515,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             )
             raise SynapseError(
                 code=400,
-                msg=self.hs.config.limit_remote_rooms.complexity_error,
+                msg=self.hs.config.server.limit_remote_rooms.complexity_error,
                 errcode=Codes.RESOURCE_LIMIT_EXCEEDED,
             )
 
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 8226d6f5a1..6d3333ee00 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -105,7 +105,7 @@ class SearchHandler(BaseHandler):
             dict to be returned to the client with results of search
         """
 
-        if not self.hs.config.enable_search:
+        if not self.hs.config.server.enable_search:
             raise SynapseError(400, "Search is disabled on this homeserver")
 
         batch_group = None
diff --git a/synapse/handlers/send_email.py b/synapse/handlers/send_email.py
index 25e6b012b7..1a062a784c 100644
--- a/synapse/handlers/send_email.py
+++ b/synapse/handlers/send_email.py
@@ -105,8 +105,13 @@ async def _sendmail(
         # set to enable TLS.
         factory = build_sender_factory(hostname=smtphost if enable_tls else None)
 
-    # the IReactorTCP interface claims host has to be a bytes, which seems to be wrong
-    reactor.connectTCP(smtphost, smtpport, factory, timeout=30, bindAddress=None)  # type: ignore[arg-type]
+    reactor.connectTCP(
+        smtphost,  # type: ignore[arg-type]
+        smtpport,
+        factory,
+        timeout=30,
+        bindAddress=None,
+    )
 
     await make_deferred_yieldable(d)
 
diff --git a/synapse/handlers/ui_auth/checkers.py b/synapse/handlers/ui_auth/checkers.py
index 8f5d465fa1..184730ebe8 100644
--- a/synapse/handlers/ui_auth/checkers.py
+++ b/synapse/handlers/ui_auth/checkers.py
@@ -153,21 +153,23 @@ class _BaseThreepidAuthChecker:
 
         # msisdns are currently always ThreepidBehaviour.REMOTE
         if medium == "msisdn":
-            if not self.hs.config.account_threepid_delegate_msisdn:
+            if not self.hs.config.registration.account_threepid_delegate_msisdn:
                 raise SynapseError(
                     400, "Phone number verification is not enabled on this homeserver"
                 )
             threepid = await identity_handler.threepid_from_creds(
-                self.hs.config.account_threepid_delegate_msisdn, threepid_creds
+                self.hs.config.registration.account_threepid_delegate_msisdn,
+                threepid_creds,
             )
         elif medium == "email":
             if (
                 self.hs.config.email.threepid_behaviour_email
                 == ThreepidBehaviour.REMOTE
             ):
-                assert self.hs.config.account_threepid_delegate_email
+                assert self.hs.config.registration.account_threepid_delegate_email
                 threepid = await identity_handler.threepid_from_creds(
-                    self.hs.config.account_threepid_delegate_email, threepid_creds
+                    self.hs.config.registration.account_threepid_delegate_email,
+                    threepid_creds,
                 )
             elif (
                 self.hs.config.email.threepid_behaviour_email == ThreepidBehaviour.LOCAL
@@ -240,7 +242,7 @@ class MsisdnAuthChecker(UserInteractiveAuthChecker, _BaseThreepidAuthChecker):
         _BaseThreepidAuthChecker.__init__(self, hs)
 
     def is_enabled(self) -> bool:
-        return bool(self.hs.config.account_threepid_delegate_msisdn)
+        return bool(self.hs.config.registration.account_threepid_delegate_msisdn)
 
     async def check_auth(self, authdict: dict, clientip: str) -> Any:
         return await self._check_threepid("msisdn", authdict)
@@ -252,7 +254,7 @@ class RegistrationTokenAuthChecker(UserInteractiveAuthChecker):
     def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
         self.hs = hs
-        self._enabled = bool(hs.config.registration_requires_token)
+        self._enabled = bool(hs.config.registration.registration_requires_token)
         self.store = hs.get_datastore()
 
     def is_enabled(self) -> bool:
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index b91e7cb501..18d8c8744e 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -60,7 +60,7 @@ class UserDirectoryHandler(StateDeltasHandler):
         self.clock = hs.get_clock()
         self.notifier = hs.get_notifier()
         self.is_mine_id = hs.is_mine_id
-        self.update_user_directory = hs.config.update_user_directory
+        self.update_user_directory = hs.config.server.update_user_directory
         self.search_all_users = hs.config.userdirectory.user_directory_search_all_users
         self.spam_checker = hs.get_spam_checker()
         # The current position in the current_state_delta stream
@@ -132,12 +132,7 @@ class UserDirectoryHandler(StateDeltasHandler):
         # FIXME(#3714): We should probably do this in the same worker as all
         # the other changes.
 
-        # Support users are for diagnostics and should not appear in the user directory.
-        is_support = await self.store.is_support_user(user_id)
-        # When change profile information of deactivated user it should not appear in the user directory.
-        is_deactivated = await self.store.get_user_deactivated_status(user_id)
-
-        if not (is_support or is_deactivated):
+        if await self.store.should_include_local_user_in_dir(user_id):
             await self.store.update_profile_in_user_dir(
                 user_id, profile.display_name, profile.avatar_url
             )
@@ -229,8 +224,10 @@ class UserDirectoryHandler(StateDeltasHandler):
                     else:
                         logger.debug("Server is still in room: %r", room_id)
 
-                is_support = await self.store.is_support_user(state_key)
-                if not is_support:
+                include_in_dir = not self.is_mine_id(
+                    state_key
+                ) or await self.store.should_include_local_user_in_dir(state_key)
+                if include_in_dir:
                     if change is MatchChange.no_change:
                         # Handle any profile changes
                         await self._handle_profile_change(
@@ -356,13 +353,7 @@ class UserDirectoryHandler(StateDeltasHandler):
 
             # First, if they're our user then we need to update for every user
             if self.is_mine_id(user_id):
-
-                is_appservice = self.store.get_if_app_services_interested_in_user(
-                    user_id
-                )
-
-                # We don't care about appservice users.
-                if not is_appservice:
+                if await self.store.should_include_local_user_in_dir(user_id):
                     for other_user_id in other_users_in_room:
                         if user_id == other_user_id:
                             continue
@@ -374,10 +365,10 @@ class UserDirectoryHandler(StateDeltasHandler):
                 if user_id == other_user_id:
                     continue
 
-                is_appservice = self.store.get_if_app_services_interested_in_user(
+                include_other_user = self.is_mine_id(
                     other_user_id
-                )
-                if self.is_mine_id(other_user_id) and not is_appservice:
+                ) and await self.store.should_include_local_user_in_dir(other_user_id)
+                if include_other_user:
                     to_insert.add((other_user_id, user_id))
 
             if to_insert:
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index cdc36b8d25..4f59224686 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -327,23 +327,23 @@ class MatrixFederationHttpClient:
         self.reactor = hs.get_reactor()
 
         user_agent = hs.version_string
-        if hs.config.user_agent_suffix:
-            user_agent = "%s %s" % (user_agent, hs.config.user_agent_suffix)
+        if hs.config.server.user_agent_suffix:
+            user_agent = "%s %s" % (user_agent, hs.config.server.user_agent_suffix)
         user_agent = user_agent.encode("ascii")
 
         federation_agent = MatrixFederationAgent(
             self.reactor,
             tls_client_options_factory,
             user_agent,
-            hs.config.federation_ip_range_whitelist,
-            hs.config.federation_ip_range_blacklist,
+            hs.config.server.federation_ip_range_whitelist,
+            hs.config.server.federation_ip_range_blacklist,
         )
 
         # Use a BlacklistingAgentWrapper to prevent circumventing the IP
         # blacklist via IP literals in server names
         self.agent = BlacklistingAgentWrapper(
             federation_agent,
-            ip_blacklist=hs.config.federation_ip_range_blacklist,
+            ip_blacklist=hs.config.server.federation_ip_range_blacklist,
         )
 
         self.clock = hs.get_clock()
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index 03d2dd94f6..5276c4bfcc 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -339,6 +339,7 @@ def ensure_active_span(message, ret=None):
                     "There was no active span when trying to %s."
                     " Did you forget to start one or did a context slip?",
                     message,
+                    stack_info=True,
                 )
 
                 return ret
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index 1438a82b60..d64d1dbacd 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -315,7 +315,7 @@ class ReplicationCommandHandler:
                 hs, outbound_redis_connection
             )
             hs.get_reactor().connectTCP(
-                hs.config.redis.redis_host.encode(),
+                hs.config.redis.redis_host,  # type: ignore[arg-type]
                 hs.config.redis.redis_port,
                 self._factory,
             )
@@ -324,7 +324,11 @@ class ReplicationCommandHandler:
             self._factory = DirectTcpReplicationClientFactory(hs, client_name, self)
             host = hs.config.worker.worker_replication_host
             port = hs.config.worker.worker_replication_port
-            hs.get_reactor().connectTCP(host.encode(), port, self._factory)
+            hs.get_reactor().connectTCP(
+                host,  # type: ignore[arg-type]
+                port,
+                self._factory,
+            )
 
     def get_streams(self) -> Dict[str, Stream]:
         """Get a map from stream name to all streams."""
diff --git a/synapse/replication/tcp/redis.py b/synapse/replication/tcp/redis.py
index 8c0df627c8..062fe2f33e 100644
--- a/synapse/replication/tcp/redis.py
+++ b/synapse/replication/tcp/redis.py
@@ -364,6 +364,12 @@ def lazyConnection(
     factory.continueTrying = reconnect
 
     reactor = hs.get_reactor()
-    reactor.connectTCP(host.encode(), port, factory, timeout=30, bindAddress=None)
+    reactor.connectTCP(
+        host,  # type: ignore[arg-type]
+        port,
+        factory,
+        timeout=30,
+        bindAddress=None,
+    )
 
     return factory.handler
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 030852cb5b..80f9b23bfd 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -71,7 +71,7 @@ class ReplicationStreamer:
         self.notifier = hs.get_notifier()
         self._instance_name = hs.get_instance_name()
 
-        self._replication_torture_level = hs.config.replication_torture_level
+        self._replication_torture_level = hs.config.server.replication_torture_level
 
         self.notifier.add_replication_callback(self.on_notifier_poke)
 
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 46bfec4623..f20aa65301 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -442,7 +442,7 @@ class UserRegisterServlet(RestServlet):
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
         self._clear_old_nonces()
 
-        if not self.hs.config.registration_shared_secret:
+        if not self.hs.config.registration.registration_shared_secret:
             raise SynapseError(400, "Shared secret registration is not enabled")
 
         body = parse_json_object_from_request(request)
@@ -498,7 +498,7 @@ class UserRegisterServlet(RestServlet):
         got_mac = body["mac"]
 
         want_mac_builder = hmac.new(
-            key=self.hs.config.registration_shared_secret.encode(),
+            key=self.hs.config.registration.registration_shared_secret.encode(),
             digestmod=hashlib.sha1,
         )
         want_mac_builder.update(nonce.encode("utf8"))
diff --git a/synapse/rest/client/account.py b/synapse/rest/client/account.py
index 6a7608d60b..6b272658fc 100644
--- a/synapse/rest/client/account.py
+++ b/synapse/rest/client/account.py
@@ -119,7 +119,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is None:
-            if self.config.request_token_inhibit_3pid_errors:
+            if self.config.server.request_token_inhibit_3pid_errors:
                 # Make the client think the operation succeeded. See the rationale in the
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
@@ -130,11 +130,11 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email not found", Codes.THREEPID_NOT_FOUND)
 
         if self.config.email.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
-            assert self.hs.config.account_threepid_delegate_email
+            assert self.hs.config.registration.account_threepid_delegate_email
 
             # Have the configured identity server handle the request
             ret = await self.identity_handler.requestEmailToken(
-                self.hs.config.account_threepid_delegate_email,
+                self.hs.config.registration.account_threepid_delegate_email,
                 email,
                 client_secret,
                 send_attempt,
@@ -403,7 +403,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
         existing_user_id = await self.store.get_user_id_by_threepid("email", email)
 
         if existing_user_id is not None:
-            if self.config.request_token_inhibit_3pid_errors:
+            if self.config.server.request_token_inhibit_3pid_errors:
                 # Make the client think the operation succeeded. See the rationale in the
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
@@ -414,11 +414,11 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         if self.config.email.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
-            assert self.hs.config.account_threepid_delegate_email
+            assert self.hs.config.registration.account_threepid_delegate_email
 
             # Have the configured identity server handle the request
             ret = await self.identity_handler.requestEmailToken(
-                self.hs.config.account_threepid_delegate_email,
+                self.hs.config.registration.account_threepid_delegate_email,
                 email,
                 client_secret,
                 send_attempt,
@@ -486,7 +486,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
         existing_user_id = await self.store.get_user_id_by_threepid("msisdn", msisdn)
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
+            if self.hs.config.server.request_token_inhibit_3pid_errors:
                 # Make the client think the operation succeeded. See the rationale in the
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
@@ -496,7 +496,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
 
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
-        if not self.hs.config.account_threepid_delegate_msisdn:
+        if not self.hs.config.registration.account_threepid_delegate_msisdn:
             logger.warning(
                 "No upstream msisdn account_threepid_delegate configured on the server to "
                 "handle this request"
@@ -507,7 +507,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
             )
 
         ret = await self.identity_handler.requestMsisdnToken(
-            self.hs.config.account_threepid_delegate_msisdn,
+            self.hs.config.registration.account_threepid_delegate_msisdn,
             country,
             phone_number,
             client_secret,
@@ -604,7 +604,7 @@ class AddThreepidMsisdnSubmitTokenServlet(RestServlet):
         self.identity_handler = hs.get_identity_handler()
 
     async def on_POST(self, request: Request) -> Tuple[int, JsonDict]:
-        if not self.config.account_threepid_delegate_msisdn:
+        if not self.config.registration.account_threepid_delegate_msisdn:
             raise SynapseError(
                 400,
                 "This homeserver is not validating phone numbers. Use an identity server "
@@ -617,7 +617,7 @@ class AddThreepidMsisdnSubmitTokenServlet(RestServlet):
 
         # Proxy submit_token request to msisdn threepid delegate
         response = await self.identity_handler.proxy_msisdn_submit_token(
-            self.config.account_threepid_delegate_msisdn,
+            self.config.registration.account_threepid_delegate_msisdn,
             body["client_secret"],
             body["sid"],
             body["token"],
@@ -644,7 +644,7 @@ class ThreepidRestServlet(RestServlet):
         return 200, {"threepids": threepids}
 
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        if not self.hs.config.enable_3pid_changes:
+        if not self.hs.config.registration.enable_3pid_changes:
             raise SynapseError(
                 400, "3PID changes are disabled on this server", Codes.FORBIDDEN
             )
@@ -693,7 +693,7 @@ class ThreepidAddRestServlet(RestServlet):
 
     @interactive_auth_handler
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        if not self.hs.config.enable_3pid_changes:
+        if not self.hs.config.registration.enable_3pid_changes:
             raise SynapseError(
                 400, "3PID changes are disabled on this server", Codes.FORBIDDEN
             )
@@ -801,7 +801,7 @@ class ThreepidDeleteRestServlet(RestServlet):
         self.auth_handler = hs.get_auth_handler()
 
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        if not self.hs.config.enable_3pid_changes:
+        if not self.hs.config.registration.enable_3pid_changes:
             raise SynapseError(
                 400, "3PID changes are disabled on this server", Codes.FORBIDDEN
             )
@@ -857,8 +857,8 @@ def assert_valid_next_link(hs: "HomeServer", next_link: str) -> None:
     # If the domain whitelist is set, the domain must be in it
     if (
         valid
-        and hs.config.next_link_domain_whitelist is not None
-        and next_link_parsed.hostname not in hs.config.next_link_domain_whitelist
+        and hs.config.server.next_link_domain_whitelist is not None
+        and next_link_parsed.hostname not in hs.config.server.next_link_domain_whitelist
     ):
         valid = False
 
@@ -878,9 +878,13 @@ class WhoamiRestServlet(RestServlet):
         self.auth = hs.get_auth()
 
     async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        requester = await self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        response = {"user_id": requester.user.to_string()}
+        response = {
+            "user_id": requester.user.to_string(),
+            # MSC: https://github.com/matrix-org/matrix-doc/pull/3069
+            "org.matrix.msc3069.is_guest": bool(requester.is_guest),
+        }
 
         # Appservices and similar accounts do not have device IDs
         # that we can report on, so exclude them for compliance.
diff --git a/synapse/rest/client/auth.py b/synapse/rest/client/auth.py
index 282861fae2..c9ad35a3ad 100644
--- a/synapse/rest/client/auth.py
+++ b/synapse/rest/client/auth.py
@@ -49,8 +49,10 @@ class AuthRestServlet(RestServlet):
         self.registration_handler = hs.get_registration_handler()
         self.recaptcha_template = hs.config.captcha.recaptcha_template
         self.terms_template = hs.config.terms_template
-        self.registration_token_template = hs.config.registration_token_template
-        self.success_template = hs.config.fallback_success_template
+        self.registration_token_template = (
+            hs.config.registration.registration_token_template
+        )
+        self.success_template = hs.config.registration.fallback_success_template
 
     async def on_GET(self, request: SynapseRequest, stagetype: str) -> None:
         session = parse_string(request, "session")
diff --git a/synapse/rest/client/capabilities.py b/synapse/rest/client/capabilities.py
index 65b3b5ce2c..2a3e24ae7e 100644
--- a/synapse/rest/client/capabilities.py
+++ b/synapse/rest/client/capabilities.py
@@ -44,10 +44,10 @@ class CapabilitiesRestServlet(RestServlet):
         await self.auth.get_user_by_req(request, allow_guest=True)
         change_password = self.auth_handler.can_change_password()
 
-        response = {
+        response: JsonDict = {
             "capabilities": {
                 "m.room_versions": {
-                    "default": self.config.default_room_version.identifier,
+                    "default": self.config.server.default_room_version.identifier,
                     "available": {
                         v.identifier: v.disposition
                         for v in KNOWN_ROOM_VERSIONS.values()
@@ -64,13 +64,13 @@ class CapabilitiesRestServlet(RestServlet):
 
         if self.config.experimental.msc3283_enabled:
             response["capabilities"]["org.matrix.msc3283.set_displayname"] = {
-                "enabled": self.config.enable_set_displayname
+                "enabled": self.config.registration.enable_set_displayname
             }
             response["capabilities"]["org.matrix.msc3283.set_avatar_url"] = {
-                "enabled": self.config.enable_set_avatar_url
+                "enabled": self.config.registration.enable_set_avatar_url
             }
             response["capabilities"]["org.matrix.msc3283.3pid_changes"] = {
-                "enabled": self.config.enable_3pid_changes
+                "enabled": self.config.registration.enable_3pid_changes
             }
 
         return 200, response
diff --git a/synapse/rest/client/filter.py b/synapse/rest/client/filter.py
index 6ed60c7418..cc1c2f9731 100644
--- a/synapse/rest/client/filter.py
+++ b/synapse/rest/client/filter.py
@@ -90,7 +90,7 @@ class CreateFilterRestServlet(RestServlet):
             raise AuthError(403, "Can only create filters for local users")
 
         content = parse_json_object_from_request(request)
-        set_timeline_upper_limit(content, self.hs.config.filter_timeline_limit)
+        set_timeline_upper_limit(content, self.hs.config.server.filter_timeline_limit)
 
         filter_id = await self.filtering.add_user_filter(
             user_localpart=target_user.localpart, user_filter=content
diff --git a/synapse/rest/client/login.py b/synapse/rest/client/login.py
index fa5c173f4b..d49a647b03 100644
--- a/synapse/rest/client/login.py
+++ b/synapse/rest/client/login.py
@@ -79,7 +79,7 @@ class LoginRestServlet(RestServlet):
         self.saml2_enabled = hs.config.saml2.saml2_enabled
         self.cas_enabled = hs.config.cas.cas_enabled
         self.oidc_enabled = hs.config.oidc.oidc_enabled
-        self._msc2918_enabled = hs.config.access_token_lifetime is not None
+        self._msc2918_enabled = hs.config.registration.access_token_lifetime is not None
 
         self.auth = hs.get_auth()
 
@@ -447,7 +447,7 @@ class RefreshTokenServlet(RestServlet):
     def __init__(self, hs: "HomeServer"):
         self._auth_handler = hs.get_auth_handler()
         self._clock = hs.get_clock()
-        self.access_token_lifetime = hs.config.access_token_lifetime
+        self.access_token_lifetime = hs.config.registration.access_token_lifetime
 
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
         refresh_submission = parse_json_object_from_request(request)
@@ -556,7 +556,7 @@ class CasTicketServlet(RestServlet):
 
 def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     LoginRestServlet(hs).register(http_server)
-    if hs.config.access_token_lifetime is not None:
+    if hs.config.registration.access_token_lifetime is not None:
         RefreshTokenServlet(hs).register(http_server)
     SsoRedirectServlet(hs).register(http_server)
     if hs.config.cas.cas_enabled:
diff --git a/synapse/rest/client/profile.py b/synapse/rest/client/profile.py
index d0f20de569..c684636c0a 100644
--- a/synapse/rest/client/profile.py
+++ b/synapse/rest/client/profile.py
@@ -41,7 +41,7 @@ class ProfileDisplaynameRestServlet(RestServlet):
     ) -> Tuple[int, JsonDict]:
         requester_user = None
 
-        if self.hs.config.require_auth_for_profile_requests:
+        if self.hs.config.server.require_auth_for_profile_requests:
             requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
@@ -94,7 +94,7 @@ class ProfileAvatarURLRestServlet(RestServlet):
     ) -> Tuple[int, JsonDict]:
         requester_user = None
 
-        if self.hs.config.require_auth_for_profile_requests:
+        if self.hs.config.server.require_auth_for_profile_requests:
             requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
@@ -146,7 +146,7 @@ class ProfileRestServlet(RestServlet):
     ) -> Tuple[int, JsonDict]:
         requester_user = None
 
-        if self.hs.config.require_auth_for_profile_requests:
+        if self.hs.config.server.require_auth_for_profile_requests:
             requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
diff --git a/synapse/rest/client/register.py b/synapse/rest/client/register.py
index 48b0062cf4..bf3cb34146 100644
--- a/synapse/rest/client/register.py
+++ b/synapse/rest/client/register.py
@@ -129,7 +129,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
+            if self.hs.config.server.request_token_inhibit_3pid_errors:
                 # Make the client think the operation succeeded. See the rationale in the
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
@@ -140,11 +140,11 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         if self.config.email.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
-            assert self.hs.config.account_threepid_delegate_email
+            assert self.hs.config.registration.account_threepid_delegate_email
 
             # Have the configured identity server handle the request
             ret = await self.identity_handler.requestEmailToken(
-                self.hs.config.account_threepid_delegate_email,
+                self.hs.config.registration.account_threepid_delegate_email,
                 email,
                 client_secret,
                 send_attempt,
@@ -209,7 +209,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
+            if self.hs.config.server.request_token_inhibit_3pid_errors:
                 # Make the client think the operation succeeded. See the rationale in the
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
@@ -221,7 +221,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
                 400, "Phone number is already in use", Codes.THREEPID_IN_USE
             )
 
-        if not self.hs.config.account_threepid_delegate_msisdn:
+        if not self.hs.config.registration.account_threepid_delegate_msisdn:
             logger.warning(
                 "No upstream msisdn account_threepid_delegate configured on the server to "
                 "handle this request"
@@ -231,7 +231,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
             )
 
         ret = await self.identity_handler.requestMsisdnToken(
-            self.hs.config.account_threepid_delegate_msisdn,
+            self.hs.config.registration.account_threepid_delegate_msisdn,
             country,
             phone_number,
             client_secret,
@@ -341,7 +341,7 @@ class UsernameAvailabilityRestServlet(RestServlet):
         )
 
     async def on_GET(self, request: Request) -> Tuple[int, JsonDict]:
-        if not self.hs.config.enable_registration:
+        if not self.hs.config.registration.enable_registration:
             raise SynapseError(
                 403, "Registration has been disabled", errcode=Codes.FORBIDDEN
             )
@@ -391,7 +391,7 @@ class RegistrationTokenValidityRestServlet(RestServlet):
     async def on_GET(self, request: Request) -> Tuple[int, JsonDict]:
         await self.ratelimiter.ratelimit(None, (request.getClientIP(),))
 
-        if not self.hs.config.enable_registration:
+        if not self.hs.config.registration.enable_registration:
             raise SynapseError(
                 403, "Registration has been disabled", errcode=Codes.FORBIDDEN
             )
@@ -419,8 +419,8 @@ class RegisterRestServlet(RestServlet):
         self.ratelimiter = hs.get_registration_ratelimiter()
         self.password_policy_handler = hs.get_password_policy_handler()
         self.clock = hs.get_clock()
-        self._registration_enabled = self.hs.config.enable_registration
-        self._msc2918_enabled = hs.config.access_token_lifetime is not None
+        self._registration_enabled = self.hs.config.registration.enable_registration
+        self._msc2918_enabled = hs.config.registration.access_token_lifetime is not None
 
         self._registration_flows = _calculate_registration_flows(
             hs.config, self.auth_handler
@@ -682,7 +682,7 @@ class RegisterRestServlet(RestServlet):
             # written to the db
             if threepid:
                 if is_threepid_reserved(
-                    self.hs.config.mau_limits_reserved_threepids, threepid
+                    self.hs.config.server.mau_limits_reserved_threepids, threepid
                 ):
                     await self.store.upsert_monthly_active_user(registered_user_id)
 
@@ -800,7 +800,7 @@ class RegisterRestServlet(RestServlet):
     async def _do_guest_registration(
         self, params: JsonDict, address: Optional[str] = None
     ) -> Tuple[int, JsonDict]:
-        if not self.hs.config.allow_guest_access:
+        if not self.hs.config.registration.allow_guest_access:
             raise SynapseError(403, "Guest access is disabled")
         user_id = await self.registration_handler.register_user(
             make_guest=True, address=address
@@ -849,13 +849,13 @@ def _calculate_registration_flows(
     """
     # FIXME: need a better error than "no auth flow found" for scenarios
     # where we required 3PID for registration but the user didn't give one
-    require_email = "email" in config.registrations_require_3pid
-    require_msisdn = "msisdn" in config.registrations_require_3pid
+    require_email = "email" in config.registration.registrations_require_3pid
+    require_msisdn = "msisdn" in config.registration.registrations_require_3pid
 
     show_msisdn = True
     show_email = True
 
-    if config.disable_msisdn_registration:
+    if config.registration.disable_msisdn_registration:
         show_msisdn = False
         require_msisdn = False
 
@@ -909,7 +909,7 @@ def _calculate_registration_flows(
             flow.insert(0, LoginType.RECAPTCHA)
 
     # Prepend registration token to all flows if we're requiring a token
-    if config.registration_requires_token:
+    if config.registration.registration_requires_token:
         for flow in flows:
             flow.insert(0, LoginType.REGISTRATION_TOKEN)
 
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index bf46dc60f2..ed95189b6d 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -369,7 +369,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
             # Option to allow servers to require auth when accessing
             # /publicRooms via CS API. This is especially helpful in private
             # federations.
-            if not self.hs.config.allow_public_rooms_without_auth:
+            if not self.hs.config.server.allow_public_rooms_without_auth:
                 raise
 
             # We allow people to not be authed if they're just looking at our
diff --git a/synapse/rest/client/room_batch.py b/synapse/rest/client/room_batch.py
index bf14ec384e..1dffcc3147 100644
--- a/synapse/rest/client/room_batch.py
+++ b/synapse/rest/client/room_batch.py
@@ -306,11 +306,13 @@ class RoomBatchSendEventRestServlet(RestServlet):
             # Verify the batch_id_from_query corresponds to an actual insertion event
             # and have the batch connected.
             corresponding_insertion_event_id = (
-                await self.store.get_insertion_event_by_batch_id(batch_id_from_query)
+                await self.store.get_insertion_event_by_batch_id(
+                    room_id, batch_id_from_query
+                )
             )
             if corresponding_insertion_event_id is None:
                 raise SynapseError(
-                    400,
+                    HTTPStatus.BAD_REQUEST,
                     "No insertion event corresponds to the given ?batch_id",
                     errcode=Codes.INVALID_PARAM,
                 )
diff --git a/synapse/rest/client/shared_rooms.py b/synapse/rest/client/shared_rooms.py
index 1d90493eb0..09a46737de 100644
--- a/synapse/rest/client/shared_rooms.py
+++ b/synapse/rest/client/shared_rooms.py
@@ -42,7 +42,7 @@ class UserSharedRoomsServlet(RestServlet):
         super().__init__()
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
-        self.user_directory_active = hs.config.update_user_directory
+        self.user_directory_active = hs.config.server.update_user_directory
 
     async def on_GET(
         self, request: SynapseRequest, user_id: str
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index 1259058b9b..913216a7c4 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -155,7 +155,7 @@ class SyncRestServlet(RestServlet):
             try:
                 filter_object = json_decoder.decode(filter_id)
                 set_timeline_upper_limit(
-                    filter_object, self.hs.config.filter_timeline_limit
+                    filter_object, self.hs.config.server.filter_timeline_limit
                 )
             except Exception:
                 raise SynapseError(400, "Invalid filter JSON")
diff --git a/synapse/rest/client/voip.py b/synapse/rest/client/voip.py
index ea2b8aa45f..ea7e025156 100644
--- a/synapse/rest/client/voip.py
+++ b/synapse/rest/client/voip.py
@@ -70,7 +70,7 @@ class VoipRestServlet(RestServlet):
             {
                 "username": username,
                 "password": password,
-                "ttl": userLifetime / 1000,
+                "ttl": userLifetime // 1000,
                 "uris": turnUris,
             },
         )
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 79a42b2455..044f44a397 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -73,6 +73,7 @@ OG_TAG_VALUE_MAXLEN = 1000
 
 ONE_HOUR = 60 * 60 * 1000
 ONE_DAY = 24 * ONE_HOUR
+IMAGE_CACHE_EXPIRY_MS = 2 * ONE_DAY
 
 
 @attr.s(slots=True, frozen=True, auto_attribs=True)
@@ -496,6 +497,27 @@ class PreviewUrlResource(DirectServeJsonResource):
             logger.info("Still running DB updates; skipping expiry")
             return
 
+        def try_remove_parent_dirs(dirs: Iterable[str]) -> None:
+            """Attempt to remove the given chain of parent directories
+
+            Args:
+                dirs: The list of directory paths to delete, with children appearing
+                    before their parents.
+            """
+            for dir in dirs:
+                try:
+                    os.rmdir(dir)
+                except FileNotFoundError:
+                    # Already deleted, continue with deleting the rest
+                    pass
+                except OSError as e:
+                    # Failed, skip deleting the rest of the parent dirs
+                    if e.errno != errno.ENOTEMPTY:
+                        logger.warning(
+                            "Failed to remove media directory: %r: %s", dir, e
+                        )
+                    break
+
         # First we delete expired url cache entries
         media_ids = await self.store.get_expired_url_cache(now)
 
@@ -504,20 +526,16 @@ class PreviewUrlResource(DirectServeJsonResource):
             fname = self.filepaths.url_cache_filepath(media_id)
             try:
                 os.remove(fname)
+            except FileNotFoundError:
+                pass  # If the path doesn't exist, meh
             except OSError as e:
-                # If the path doesn't exist, meh
-                if e.errno != errno.ENOENT:
-                    logger.warning("Failed to remove media: %r: %s", media_id, e)
-                    continue
+                logger.warning("Failed to remove media: %r: %s", media_id, e)
+                continue
 
             removed_media.append(media_id)
 
-            try:
-                dirs = self.filepaths.url_cache_filepath_dirs_to_delete(media_id)
-                for dir in dirs:
-                    os.rmdir(dir)
-            except Exception:
-                pass
+            dirs = self.filepaths.url_cache_filepath_dirs_to_delete(media_id)
+            try_remove_parent_dirs(dirs)
 
         await self.store.delete_url_cache(removed_media)
 
@@ -530,7 +548,7 @@ class PreviewUrlResource(DirectServeJsonResource):
         # These may be cached for a bit on the client (i.e., they
         # may have a room open with a preview url thing open).
         # So we wait a couple of days before deleting, just in case.
-        expire_before = now - 2 * ONE_DAY
+        expire_before = now - IMAGE_CACHE_EXPIRY_MS
         media_ids = await self.store.get_url_cache_media_before(expire_before)
 
         removed_media = []
@@ -538,36 +556,30 @@ class PreviewUrlResource(DirectServeJsonResource):
             fname = self.filepaths.url_cache_filepath(media_id)
             try:
                 os.remove(fname)
+            except FileNotFoundError:
+                pass  # If the path doesn't exist, meh
             except OSError as e:
-                # If the path doesn't exist, meh
-                if e.errno != errno.ENOENT:
-                    logger.warning("Failed to remove media: %r: %s", media_id, e)
-                    continue
+                logger.warning("Failed to remove media: %r: %s", media_id, e)
+                continue
 
-            try:
-                dirs = self.filepaths.url_cache_filepath_dirs_to_delete(media_id)
-                for dir in dirs:
-                    os.rmdir(dir)
-            except Exception:
-                pass
+            dirs = self.filepaths.url_cache_filepath_dirs_to_delete(media_id)
+            try_remove_parent_dirs(dirs)
 
             thumbnail_dir = self.filepaths.url_cache_thumbnail_directory(media_id)
             try:
                 shutil.rmtree(thumbnail_dir)
+            except FileNotFoundError:
+                pass  # If the path doesn't exist, meh
             except OSError as e:
-                # If the path doesn't exist, meh
-                if e.errno != errno.ENOENT:
-                    logger.warning("Failed to remove media: %r: %s", media_id, e)
-                    continue
+                logger.warning("Failed to remove media: %r: %s", media_id, e)
+                continue
 
             removed_media.append(media_id)
 
-            try:
-                dirs = self.filepaths.url_cache_thumbnail_dirs_to_delete(media_id)
-                for dir in dirs:
-                    os.rmdir(dir)
-            except Exception:
-                pass
+            dirs = self.filepaths.url_cache_thumbnail_dirs_to_delete(media_id)
+            # Note that one of the directories to be deleted has already been
+            # removed by the `rmtree` above.
+            try_remove_parent_dirs(dirs)
 
         await self.store.delete_url_cache_media(removed_media)
 
diff --git a/synapse/rest/well_known.py b/synapse/rest/well_known.py
index c80a3a99aa..7ac01faab4 100644
--- a/synapse/rest/well_known.py
+++ b/synapse/rest/well_known.py
@@ -39,9 +39,9 @@ class WellKnownBuilder:
 
         result = {"m.homeserver": {"base_url": self._config.server.public_baseurl}}
 
-        if self._config.default_identity_server:
+        if self._config.registration.default_identity_server:
             result["m.identity_server"] = {
-                "base_url": self._config.default_identity_server
+                "base_url": self._config.registration.default_identity_server
             }
 
         return result
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index 073b0d754f..8522930b50 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -47,9 +47,9 @@ class ResourceLimitsServerNotices:
         self._notifier = hs.get_notifier()
 
         self._enabled = (
-            hs.config.limit_usage_by_mau
+            hs.config.server.limit_usage_by_mau
             and self._server_notices_manager.is_enabled()
-            and not hs.config.hs_disabled
+            and not hs.config.server.hs_disabled
         )
 
     async def maybe_send_server_notice_to_user(self, user_id: str) -> None:
@@ -98,7 +98,7 @@ class ResourceLimitsServerNotices:
         try:
             if (
                 limit_type == LimitBlockingTypes.MONTHLY_ACTIVE_USER
-                and not self._config.mau_limit_alerting
+                and not self._config.server.mau_limit_alerting
             ):
                 # We have hit the MAU limit, but MAU alerting is disabled:
                 # reset room if necessary and return
@@ -149,7 +149,7 @@ class ResourceLimitsServerNotices:
             "body": event_body,
             "msgtype": ServerNoticeMsgType,
             "server_notice_type": ServerNoticeLimitReached,
-            "admin_contact": self._config.admin_contact,
+            "admin_contact": self._config.server.admin_contact,
             "limit_type": event_limit_type,
         }
         event = await self._server_notices_manager.send_notice(
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
index 92336d7cc8..017e6fd92d 100644
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@@ -329,12 +329,10 @@ def _resolve_auth_events(
         auth_events[(prev_event.type, prev_event.state_key)] = prev_event
         try:
             # The signatures have already been checked at this point
-            event_auth.check(
+            event_auth.check_auth_rules_for_event(
                 RoomVersions.V1,
                 event,
                 auth_events,
-                do_sig_check=False,
-                do_size_check=False,
             )
             prev_event = event
         except AuthError:
@@ -349,12 +347,10 @@ def _resolve_normal_events(
     for event in _ordered_events(events):
         try:
             # The signatures have already been checked at this point
-            event_auth.check(
+            event_auth.check_auth_rules_for_event(
                 RoomVersions.V1,
                 event,
                 auth_events,
-                do_sig_check=False,
-                do_size_check=False,
             )
             return event
         except AuthError:
diff --git a/synapse/state/v2.py b/synapse/state/v2.py
index 7b1e8361de..586b0e12fe 100644
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@@ -546,12 +546,10 @@ async def _iterative_auth_checks(
                     auth_events[key] = event_map[ev_id]
 
         try:
-            event_auth.check(
+            event_auth.check_auth_rules_for_event(
                 room_version,
                 event,
                 auth_events,
-                do_sig_check=False,
-                do_size_check=False,
             )
 
             resolved_state[(event.type, event.state_key)] = event_id
diff --git a/synapse/storage/databases/main/censor_events.py b/synapse/storage/databases/main/censor_events.py
index 6305414e3d..eee07227ef 100644
--- a/synapse/storage/databases/main/censor_events.py
+++ b/synapse/storage/databases/main/censor_events.py
@@ -36,7 +36,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
 
         if (
             hs.config.worker.run_background_tasks
-            and self.hs.config.redaction_retention_period is not None
+            and self.hs.config.server.redaction_retention_period is not None
         ):
             hs.get_clock().looping_call(self._censor_redactions, 5 * 60 * 1000)
 
@@ -48,7 +48,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
         By censor we mean update the event_json table with the redacted event.
         """
 
-        if self.hs.config.redaction_retention_period is None:
+        if self.hs.config.server.redaction_retention_period is None:
             return
 
         if not (
@@ -60,7 +60,9 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
             # created.
             return
 
-        before_ts = self._clock.time_msec() - self.hs.config.redaction_retention_period
+        before_ts = (
+            self._clock.time_msec() - self.hs.config.server.redaction_retention_period
+        )
 
         # We fetch all redactions that:
         #   1. point to an event we have,
diff --git a/synapse/storage/databases/main/client_ips.py b/synapse/storage/databases/main/client_ips.py
index cc192f5c87..c77acc7c84 100644
--- a/synapse/storage/databases/main/client_ips.py
+++ b/synapse/storage/databases/main/client_ips.py
@@ -353,7 +353,7 @@ class ClientIpWorkerStore(ClientIpBackgroundUpdateStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
-        self.user_ips_max_age = hs.config.user_ips_max_age
+        self.user_ips_max_age = hs.config.server.user_ips_max_age
 
         if hs.config.worker.run_background_tasks and self.user_ips_max_age:
             self._clock.looping_call(self._prune_old_user_ips, 5 * 1000)
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 584f818ff3..bc7d213fe2 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -104,7 +104,7 @@ class PersistEventsStore:
         self._clock = hs.get_clock()
         self._instance_name = hs.get_instance_name()
 
-        self._ephemeral_messages_enabled = hs.config.enable_ephemeral_messages
+        self._ephemeral_messages_enabled = hs.config.server.enable_ephemeral_messages
         self.is_mine_id = hs.is_mine_id
 
         # Ideally we'd move these ID gens here, unfortunately some other ID
@@ -1276,13 +1276,6 @@ class PersistEventsStore:
                     logger.exception("")
                     raise
 
-                # update the stored internal_metadata to update the "outlier" flag.
-                # TODO: This is unused as of Synapse 1.31. Remove it once we are happy
-                #  to drop backwards-compatibility with 1.30.
-                metadata_json = json_encoder.encode(event.internal_metadata.get_dict())
-                sql = "UPDATE event_json SET internal_metadata = ? WHERE event_id = ?"
-                txn.execute(sql, (metadata_json, event.event_id))
-
                 # Add an entry to the ex_outlier_stream table to replicate the
                 # change in outlier status to our workers.
                 stream_order = event.internal_metadata.stream_ordering
@@ -1327,19 +1320,6 @@ class PersistEventsStore:
             d.pop("redacted_because", None)
             return d
 
-        def get_internal_metadata(event):
-            im = event.internal_metadata.get_dict()
-
-            # temporary hack for database compatibility with Synapse 1.30 and earlier:
-            # store the `outlier` flag inside the internal_metadata json as well as in
-            # the `events` table, so that if anyone rolls back to an older Synapse,
-            # things keep working. This can be removed once we are happy to drop support
-            # for that
-            if event.internal_metadata.is_outlier():
-                im["outlier"] = True
-
-            return im
-
         self.db_pool.simple_insert_many_txn(
             txn,
             table="event_json",
@@ -1348,7 +1328,7 @@ class PersistEventsStore:
                     "event_id": event.event_id,
                     "room_id": event.room_id,
                     "internal_metadata": json_encoder.encode(
-                        get_internal_metadata(event)
+                        event.internal_metadata.get_dict()
                     ),
                     "json": json_encoder.encode(event_dict(event)),
                     "format_version": event.format_version,
diff --git a/synapse/storage/databases/main/filtering.py b/synapse/storage/databases/main/filtering.py
index bb244a03c0..434986fa64 100644
--- a/synapse/storage/databases/main/filtering.py
+++ b/synapse/storage/databases/main/filtering.py
@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Union
+
 from canonicaljson import encode_canonical_json
 
 from synapse.api.errors import Codes, SynapseError
@@ -22,7 +24,9 @@ from synapse.util.caches.descriptors import cached
 
 class FilteringStore(SQLBaseStore):
     @cached(num_args=2)
-    async def get_user_filter(self, user_localpart, filter_id):
+    async def get_user_filter(
+        self, user_localpart: str, filter_id: Union[int, str]
+    ) -> JsonDict:
         # filter_id is BIGINT UNSIGNED, so if it isn't a number, fail
         # with a coherent error message rather than 500 M_UNKNOWN.
         try:
@@ -40,7 +44,7 @@ class FilteringStore(SQLBaseStore):
 
         return db_to_json(def_json)
 
-    async def add_user_filter(self, user_localpart: str, user_filter: JsonDict) -> str:
+    async def add_user_filter(self, user_localpart: str, user_filter: JsonDict) -> int:
         def_json = encode_canonical_json(user_filter)
 
         # Need an atomic transaction to SELECT the maximal ID so far then
diff --git a/synapse/storage/databases/main/monthly_active_users.py b/synapse/storage/databases/main/monthly_active_users.py
index b76ee51a9b..ec4d47a560 100644
--- a/synapse/storage/databases/main/monthly_active_users.py
+++ b/synapse/storage/databases/main/monthly_active_users.py
@@ -32,8 +32,8 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
         self._clock = hs.get_clock()
         self.hs = hs
 
-        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
-        self._max_mau_value = hs.config.max_mau_value
+        self._limit_usage_by_mau = hs.config.server.limit_usage_by_mau
+        self._max_mau_value = hs.config.server.max_mau_value
 
     @cached(num_args=0)
     async def get_monthly_active_count(self) -> int:
@@ -96,8 +96,8 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
         """
         users = []
 
-        for tp in self.hs.config.mau_limits_reserved_threepids[
-            : self.hs.config.max_mau_value
+        for tp in self.hs.config.server.mau_limits_reserved_threepids[
+            : self.hs.config.server.max_mau_value
         ]:
             user_id = await self.hs.get_datastore().get_user_id_by_threepid(
                 tp["medium"], tp["address"]
@@ -212,7 +212,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
-        self._mau_stats_only = hs.config.mau_stats_only
+        self._mau_stats_only = hs.config.server.mau_stats_only
 
         # Do not add more reserved users than the total allowable number
         self.db_pool.new_transaction(
@@ -221,7 +221,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             [],
             [],
             self._initialise_reserved_users,
-            hs.config.mau_limits_reserved_threepids[: self._max_mau_value],
+            hs.config.server.mau_limits_reserved_threepids[: self._max_mau_value],
         )
 
     def _initialise_reserved_users(self, txn, threepids):
@@ -354,3 +354,27 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                         await self.upsert_monthly_active_user(user_id)
             elif now - last_seen_timestamp > LAST_SEEN_GRANULARITY:
                 await self.upsert_monthly_active_user(user_id)
+
+    async def remove_deactivated_user_from_mau_table(self, user_id: str) -> None:
+        """
+        Removes a deactivated user from the monthly active user
+        table and resets affected caches.
+
+        Args:
+            user_id(str): the user_id to remove
+        """
+
+        rows_deleted = await self.db_pool.simple_delete(
+            table="monthly_active_users",
+            keyvalues={"user_id": user_id},
+            desc="simple_delete",
+        )
+
+        if rows_deleted != 0:
+            await self.invalidate_cache_and_stream(
+                "user_last_seen_monthly_active", (user_id,)
+            )
+            await self.invalidate_cache_and_stream("get_monthly_active_count", ())
+            await self.invalidate_cache_and_stream(
+                "get_monthly_active_count_by_service", ()
+            )
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index c83089ee63..de262fbf5a 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -207,7 +207,7 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore):
             return False
 
         now = self._clock.time_msec()
-        trial_duration_ms = self.config.mau_trial_days * 24 * 60 * 60 * 1000
+        trial_duration_ms = self.config.server.mau_trial_days * 24 * 60 * 60 * 1000
         is_trial = (now - info["creation_ts"] * 1000) < trial_duration_ms
         return is_trial
 
@@ -1710,7 +1710,7 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
         We do this by grandfathering in existing user threepids assuming that
         they used one of the server configured trusted identity servers.
         """
-        id_servers = set(self.config.trusted_third_party_id_servers)
+        id_servers = set(self.config.registration.trusted_third_party_id_servers)
 
         def _bg_user_threepids_grandfather_txn(txn):
             sql = """
diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index 118b390e93..d69eaf80ce 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -679,8 +679,8 @@ class RoomWorkerStore(SQLBaseStore):
         # policy.
         if not ret:
             return {
-                "min_lifetime": self.config.retention_default_min_lifetime,
-                "max_lifetime": self.config.retention_default_max_lifetime,
+                "min_lifetime": self.config.server.retention_default_min_lifetime,
+                "max_lifetime": self.config.server.retention_default_max_lifetime,
             }
 
         row = ret[0]
@@ -690,10 +690,10 @@ class RoomWorkerStore(SQLBaseStore):
         # The default values will be None if no default policy has been defined, or if one
         # of the attributes is missing from the default policy.
         if row["min_lifetime"] is None:
-            row["min_lifetime"] = self.config.retention_default_min_lifetime
+            row["min_lifetime"] = self.config.server.retention_default_min_lifetime
 
         if row["max_lifetime"] is None:
-            row["max_lifetime"] = self.config.retention_default_max_lifetime
+            row["max_lifetime"] = self.config.server.retention_default_max_lifetime
 
         return row
 
diff --git a/synapse/storage/databases/main/room_batch.py b/synapse/storage/databases/main/room_batch.py
index a383388757..300a563c9e 100644
--- a/synapse/storage/databases/main/room_batch.py
+++ b/synapse/storage/databases/main/room_batch.py
@@ -18,7 +18,9 @@ from synapse.storage._base import SQLBaseStore
 
 
 class RoomBatchStore(SQLBaseStore):
-    async def get_insertion_event_by_batch_id(self, batch_id: str) -> Optional[str]:
+    async def get_insertion_event_by_batch_id(
+        self, room_id: str, batch_id: str
+    ) -> Optional[str]:
         """Retrieve a insertion event ID.
 
         Args:
@@ -30,7 +32,7 @@ class RoomBatchStore(SQLBaseStore):
         """
         return await self.db_pool.simple_select_one_onecol(
             table="insertion_events",
-            keyvalues={"next_batch_id": batch_id},
+            keyvalues={"room_id": room_id, "next_batch_id": batch_id},
             retcol="event_id",
             allow_none=True,
         )
diff --git a/synapse/storage/databases/main/search.py b/synapse/storage/databases/main/search.py
index 2a1e99e17a..c85383c975 100644
--- a/synapse/storage/databases/main/search.py
+++ b/synapse/storage/databases/main/search.py
@@ -51,7 +51,7 @@ class SearchWorkerStore(SQLBaseStore):
             txn:
             entries: entries to be added to the table
         """
-        if not self.hs.config.enable_search:
+        if not self.hs.config.server.enable_search:
             return
         if isinstance(self.database_engine, PostgresEngine):
             sql = (
@@ -105,7 +105,7 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
-        if not hs.config.enable_search:
+        if not hs.config.server.enable_search:
             return
 
         self.db_pool.updates.register_background_update_handler(
diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py
index 90d65edc42..5f538947ec 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -40,12 +40,10 @@ from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
 
-
 TEMP_TABLE = "_temp_populate_user_directory"
 
 
 class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
-
     # How many records do we calculate before sending it to
     # add_users_who_share_private_rooms?
     SHARE_PRIVATE_WORKING_SET = 500
@@ -235,6 +233,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                 )
 
                 users_with_profile = await self.get_users_in_room_with_profiles(room_id)
+                # Throw away users excluded from the directory.
+                users_with_profile = {
+                    user_id: profile
+                    for user_id, profile in users_with_profile.items()
+                    if not self.hs.is_mine_id(user_id)
+                    or await self.should_include_local_user_in_dir(user_id)
+                }
 
                 # Update each user in the user directory.
                 for user_id, profile in users_with_profile.items():
@@ -246,9 +251,6 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
                 if is_public:
                     for user_id in users_with_profile:
-                        if self.get_if_app_services_interested_in_user(user_id):
-                            continue
-
                         to_insert.add(user_id)
 
                     if to_insert:
@@ -256,12 +258,12 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                         to_insert.clear()
                 else:
                     for user_id in users_with_profile:
+                        # We want the set of pairs (L, M) where L and M are
+                        # in `users_with_profile` and L is local.
+                        # Do so by looking for the local user L first.
                         if not self.hs.is_mine_id(user_id):
                             continue
 
-                        if self.get_if_app_services_interested_in_user(user_id):
-                            continue
-
                         for other_user_id in users_with_profile:
                             if user_id == other_user_id:
                                 continue
@@ -349,10 +351,11 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         )
 
         for user_id in users_to_work_on:
-            profile = await self.get_profileinfo(get_localpart_from_id(user_id))
-            await self.update_profile_in_user_dir(
-                user_id, profile.display_name, profile.avatar_url
-            )
+            if await self.should_include_local_user_in_dir(user_id):
+                profile = await self.get_profileinfo(get_localpart_from_id(user_id))
+                await self.update_profile_in_user_dir(
+                    user_id, profile.display_name, profile.avatar_url
+                )
 
             # We've finished processing a user. Delete it from the table.
             await self.db_pool.simple_delete_one(
@@ -369,6 +372,24 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
         return len(users_to_work_on)
 
+    async def should_include_local_user_in_dir(self, user: str) -> bool:
+        """Certain classes of local user are omitted from the user directory.
+        Is this user one of them?
+        """
+        # App service users aren't usually contactable, so exclude them.
+        if self.get_if_app_services_interested_in_user(user):
+            # TODO we might want to make this configurable for each app service
+            return False
+
+        # Support users are for diagnostics and should not appear in the user directory.
+        if await self.is_support_user(user):
+            return False
+
+        # Deactivated users aren't contactable, so should not appear in the user directory.
+        if await self.get_user_deactivated_status(user):
+            return False
+        return True
+
     async def is_room_world_readable_or_publicly_joinable(self, room_id: str) -> bool:
         """Check if the room is either world_readable or publically joinable"""
 
@@ -527,7 +548,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             desc="get_user_in_directory",
         )
 
-    async def update_user_directory_stream_pos(self, stream_id: int) -> None:
+    async def update_user_directory_stream_pos(self, stream_id: Optional[int]) -> None:
         await self.db_pool.simple_update_one(
             table="user_directory_stream_pos",
             keyvalues={},
@@ -537,7 +558,6 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
 
 class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
-
     # How many records do we calculate before sending it to
     # add_users_who_share_private_rooms?
     SHARE_PRIVATE_WORKING_SET = 500
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index f31880b8ec..a63eaddfdc 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -366,7 +366,7 @@ def _upgrade_existing_database(
             + "new for the server to understand"
         )
 
-    # some of the deltas assume that config.server_name is set correctly, so now
+    # some of the deltas assume that server_name is set correctly, so now
     # is a good time to run the sanity check.
     if not is_empty and "main" in databases:
         from synapse.storage.databases.main import check_database_before_upgrade
diff --git a/synapse/storage/schema/__init__.py b/synapse/storage/schema/__init__.py
index 573e05a482..1aee741a8b 100644
--- a/synapse/storage/schema/__init__.py
+++ b/synapse/storage/schema/__init__.py
@@ -12,9 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# When updating these values, please leave a short summary of the changes below.
-
-SCHEMA_VERSION = 64
+SCHEMA_VERSION = 64  # remember to update the list below when updating
 """Represents the expectations made by the codebase about the database schema
 
 This should be incremented whenever the codebase changes its requirements on the
@@ -46,7 +44,7 @@ Changes in SCHEMA_VERSION = 64:
 """
 
 
-SCHEMA_COMPAT_VERSION = 59
+SCHEMA_COMPAT_VERSION = 60  # 60: "outlier" not in internal_metadata.
 """Limit on how far the synapse codebase can be rolled back without breaking db compat
 
 This value is stored in the database, and checked on startup. If the value in the
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index bd234549bd..64daff59df 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -50,7 +50,13 @@ def _handle_frozendict(obj: Any) -> Dict[Any, Any]:
     if type(obj) is frozendict:
         # fishing the protected dict out of the object is a bit nasty,
         # but we don't really want the overhead of copying the dict.
-        return obj._dict
+        try:
+            return obj._dict
+        except AttributeError:
+            # When the C implementation of frozendict is used,
+            # there isn't a `_dict` attribute with a dict
+            # so we resort to making a copy of the frozendict
+            return dict(obj)
     raise TypeError(
         "Object of type %s is not JSON serializable" % obj.__class__.__name__
     )
diff --git a/synapse/util/threepids.py b/synapse/util/threepids.py
index baa9190a9a..389adf00f6 100644
--- a/synapse/util/threepids.py
+++ b/synapse/util/threepids.py
@@ -44,8 +44,8 @@ def check_3pid_allowed(hs: "HomeServer", medium: str, address: str) -> bool:
         bool: whether the 3PID medium/address is allowed to be added to this HS
     """
 
-    if hs.config.allowed_local_3pids:
-        for constraint in hs.config.allowed_local_3pids:
+    if hs.config.registration.allowed_local_3pids:
+        for constraint in hs.config.registration.allowed_local_3pids:
             logger.debug(
                 "Checking 3PID %s (%s) against %s (%s)",
                 address,