3 files changed, 48 insertions, 5 deletions
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 8c7ad2a407..a40d6d7961 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -120,6 +120,7 @@ class EventTypes:
     SpaceParent = "m.space.parent"
 
     MSC2716_INSERTION = "org.matrix.msc2716.insertion"
+    MSC2716_CHUNK = "org.matrix.msc2716.chunk"
     MSC2716_MARKER = "org.matrix.msc2716.marker"
 
 
@@ -198,9 +199,10 @@ class EventContentFields:
 
     # Used on normal messages to indicate they were historically imported after the fact
     MSC2716_HISTORICAL = "org.matrix.msc2716.historical"
-    # For "insertion" events
+    # For "insertion" events to indicate what the next chunk ID should be in
+    # order to connect to it
     MSC2716_NEXT_CHUNK_ID = "org.matrix.msc2716.next_chunk_id"
-    # Used on normal message events to indicate where the chunk connects to
+    # Used on "chunk" events to indicate which insertion event it connects to
     MSC2716_CHUNK_ID = "org.matrix.msc2716.chunk_id"
     # For "marker" events
     MSC2716_MARKER_INSERTION = "org.matrix.msc2716.marker.insertion"
@@ -230,3 +232,7 @@ class HistoryVisibility:
     JOINED = "joined"
     SHARED = "shared"
     WORLD_READABLE = "world_readable"
+
+
+class ReadReceiptEventFields:
+    MSC2285_HIDDEN = "org.matrix.msc2285.hidden"
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 054ab14ab6..dc662bca83 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -75,6 +75,9 @@ class Codes:
     INVALID_SIGNATURE = "M_INVALID_SIGNATURE"
     USER_DEACTIVATED = "M_USER_DEACTIVATED"
     BAD_ALIAS = "M_BAD_ALIAS"
+    # For restricted join rules.
+    UNABLE_AUTHORISE_JOIN = "M_UNABLE_TO_AUTHORISE_JOIN"
+    UNABLE_TO_GRANT_JOIN = "M_UNABLE_TO_GRANT_JOIN"
 
 
 class CodeMessageException(RuntimeError):
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index a20abc5a65..697319e52d 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Dict
+from typing import Callable, Dict, Optional
 
 import attr
 
@@ -168,7 +168,7 @@ class RoomVersions:
         msc2403_knocking=False,
     )
     MSC3083 = RoomVersion(
-        "org.matrix.msc3083",
+        "org.matrix.msc3083.v2",
         RoomDisposition.UNSTABLE,
         EventFormatVersions.V3,
         StateResolutionVersions.V2,
@@ -208,5 +208,39 @@ KNOWN_ROOM_VERSIONS: Dict[str, RoomVersion] = {
         RoomVersions.MSC3083,
         RoomVersions.V7,
     )
-    # Note that we do not include MSC2043 here unless it is enabled in the config.
+}
+
+
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class RoomVersionCapability:
+    """An object which describes the unique attributes of a room version."""
+
+    identifier: str  # the identifier for this capability
+    preferred_version: Optional[RoomVersion]
+    support_check_lambda: Callable[[RoomVersion], bool]
+
+
+MSC3244_CAPABILITIES = {
+    cap.identifier: {
+        "preferred": cap.preferred_version.identifier
+        if cap.preferred_version is not None
+        else None,
+        "support": [
+            v.identifier
+            for v in KNOWN_ROOM_VERSIONS.values()
+            if cap.support_check_lambda(v)
+        ],
+    }
+    for cap in (
+        RoomVersionCapability(
+            "knock",
+            RoomVersions.V7,
+            lambda room_version: room_version.msc2403_knocking,
+        ),
+        RoomVersionCapability(
+            "restricted",
+            None,
+            lambda room_version: room_version.msc3083_join_rules,
+        ),
+    )
 }