1 files changed, 4 insertions, 1 deletions
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 982c8d3b2f..8d5be81a92 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -1515,7 +1515,10 @@ class FederationEventHandler:
         # support it or the event is not from the room creator.
         room_version = await self._store.get_room_version(marker_event.room_id)
         create_event = await self._store.get_create_event_for_room(marker_event.room_id)
-        room_creator = create_event.content.get(EventContentFields.ROOM_CREATOR)
+        if not room_version.msc2175_implicit_room_creator:
+            room_creator = create_event.content.get(EventContentFields.ROOM_CREATOR)
+        else:
+            room_creator = create_event.sender
         if not room_version.msc2716_historical and (
             not self._config.experimental.msc2716_enabled
             or marker_event.sender != room_creator