diff --git a/synapse/handlers/sliding_sync/room_lists.py b/synapse/handlers/sliding_sync/room_lists.py
index 49c02ab56d..6edbe9a146 100644
--- a/synapse/handlers/sliding_sync/room_lists.py
+++ b/synapse/handlers/sliding_sync/room_lists.py
@@ -748,7 +748,7 @@ class SlidingSyncRoomLists:
 
         # Filtered subset of `relevant_room_map` for rooms that may have updates
         # (in the event stream)
-        relevant_rooms_to_send_map: Dict[str, RoomSyncConfig] = relevant_room_map
+        relevant_rooms_to_send_map: Mapping[str, RoomSyncConfig] = relevant_room_map
         if relevant_room_map:
             with start_active_span("filter_relevant_rooms_to_send"):
                 if from_token:
diff --git a/synapse/types/handlers/sliding_sync.py b/synapse/types/handlers/sliding_sync.py
index 26ca1639f3..ff51404549 100644
--- a/synapse/types/handlers/sliding_sync.py
+++ b/synapse/types/handlers/sliding_sync.py
@@ -200,7 +200,7 @@ class SlidingSyncResult:
         joined_count: Optional[int]
         invited_count: Optional[int]
         notif_counts: RoomNotifCounts
-        room_receipts: Sequence[ReceiptInRoom]
+        room_receipts: Optional[Sequence[ReceiptInRoom]]
 
         def __bool__(self) -> bool:
             return (