diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index 12b73546d0..71ef5952c3 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -493,6 +493,7 @@ KNOWN_ROOM_VERSIONS: Dict[str, RoomVersion] = {
         RoomVersions.V12,
         RoomVersions.MSC3757v10,
         RoomVersions.MSC3757v11,
+        RoomVersions.HydraV11,
     )
 }