diff --git a/synapse/handlers/sliding_sync/__init__.py b/synapse/handlers/sliding_sync/__init__.py
index 295d3486c4..6b77ba90f2 100644
--- a/synapse/handlers/sliding_sync/__init__.py
+++ b/synapse/handlers/sliding_sync/__init__.py
@@ -575,7 +575,7 @@ class SlidingSyncHandler:
         to_token: StreamToken,
         newly_joined: bool,
         is_dm: bool,
-        room_receipts: Sequence[ReceiptInRoom],
+        room_receipts: Optional[Sequence[ReceiptInRoom]],
     ) -> SlidingSyncResult.RoomResult:
         """
         Fetch room data for the sync response.
diff --git a/synapse/handlers/sliding_sync/room_lists.py b/synapse/handlers/sliding_sync/room_lists.py
index b465e4ab44..49c02ab56d 100644
--- a/synapse/handlers/sliding_sync/room_lists.py
+++ b/synapse/handlers/sliding_sync/room_lists.py
@@ -740,7 +740,7 @@ class SlidingSyncRoomLists:
         previous_connection_state: PerConnectionState,
         from_token: Optional[StreamToken],
         to_token: StreamToken,
-        relevant_room_map: Dict[str, RoomSyncConfig],
+        relevant_room_map: Mapping[str, RoomSyncConfig],
         receipts: Mapping[str, Sequence[ReceiptInRoom]],
     ) -> Dict[str, RoomSyncConfig]:
         """Filters the `relevant_room_map` down to those rooms that may have