2 files changed, 15 insertions, 0 deletions
diff --git a/synapse/handlers/sliding_sync/room_lists.py b/synapse/handlers/sliding_sync/room_lists.py
index a423de74bf..353c491f72 100644
--- a/synapse/handlers/sliding_sync/room_lists.py
+++ b/synapse/handlers/sliding_sync/room_lists.py
@@ -40,6 +40,7 @@ from synapse.api.constants import (
     EventTypes,
     Membership,
 )
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.events import StrippedStateEvent
 from synapse.events.utils import parse_stripped_state_event
 from synapse.logging.opentracing import start_active_span, trace
@@ -952,6 +953,15 @@ class SlidingSyncRoomLists:
             excluded_rooms=self.rooms_to_exclude_globally,
         )
 
+        # We filter out unknown room versions before we try and load any
+        # metadata about the room. They shouldn't go down sync anyway, and their
+        # metadata may be in a broken state.
+        room_for_user_list = [
+            room_for_user
+            for room_for_user in room_for_user_list
+            if room_for_user.room_version_id in KNOWN_ROOM_VERSIONS
+        ]
+
         # Remove invites from ignored users
         ignored_users = await self.store.ignored_users(user_id)
         if ignored_users:
diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py
index e321a1add2..ded7948713 100644
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -41,6 +41,7 @@ import attr
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import Codes, SynapseError
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.logging.opentracing import trace
 from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import wrap_as_background_process
@@ -1443,6 +1444,10 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
                     is_encrypted=bool(row[9]),
                 )
                 for row in txn
+                # We filter out unknown room versions proactively. They
+                # shouldn't go down sync and their metadata may be in a broken
+                # state (causing errors).
+                if row[4] in KNOWN_ROOM_VERSIONS
             }
 
         return await self.db_pool.runInteraction(