diff --git a/src/api/client_server/sync/msc4186.rs b/src/api/client_server/sync/msc4186.rs
index 74f8a397..1760f93f 100644
--- a/src/api/client_server/sync/msc4186.rs
+++ b/src/api/client_server/sync/msc4186.rs
@@ -393,6 +393,7 @@ pub(crate) async fn sync_events_v5_route(
                 &all_joined_rooms,
             )
             .await?,
+            // TODO: only include this field when it has changed
             device_one_time_keys_count: services()
                 .users
                 .count_one_time_keys(&sender_user, &sender_device)?,
@@ -972,6 +973,12 @@ fn process_room(
         return Ok(None);
     };
 
+    // TODO: invalidate current_shortstatehash and send down all(?) state events
+    // if effective requested required_state changes between requests:
+    //
+    // > If new entries are added to required_state then the server must send
+    // > down matching current state events.
+
     let need_scan = todo_room.required_state.all_events
         || todo_room
             .required_state