diff --git a/src/api/client_server/sync/msc3575.rs b/src/api/client_server/sync/msc3575.rs
index 918d9f27..47e93472 100644
--- a/src/api/client_server/sync/msc3575.rs
+++ b/src/api/client_server/sync/msc3575.rs
@@ -39,16 +39,15 @@ impl TodoRoom {
         &mut self,
         required_state: Vec<(StateEventType, String)>,
         timeline_limit: UInt,
-        known_rooms: Option<&BTreeMap<OwnedRoomId, u64>>,
+        known_rooms: &BTreeMap<OwnedRoomId, u64>,
         room_id: &RoomId,
     ) {
         self.required_state_request.extend(required_state);
         self.timeline_limit =
             self.timeline_limit.max(u64::from(timeline_limit).min(100));
         // 0 means unknown because it got out of date
-        self.roomsince = self.roomsince.min(
-            known_rooms.and_then(|k| k.get(room_id)).copied().unwrap_or(0),
-        );
+        self.roomsince =
+            self.roomsince.min(known_rooms.get(room_id).copied().unwrap_or(0));
     }
 }
 impl Default for TodoRoom {
@@ -362,7 +361,7 @@ pub(crate) async fn sync_events_v4_route(
             todo_rooms.entry(room_id.clone()).or_default().update(
                 list.room_details.required_state.clone(),
                 list.room_details.timeline_limit.unwrap_or(uint!(10)),
-                known_rooms.get(&list_id),
+                &known_rooms,
                 room_id,
             );
         }
@@ -375,16 +374,8 @@ pub(crate) async fn sync_events_v4_route(
                     .unwrap_or(UInt::MAX),
             },
         );
-
-        services().users.update_sync_known_rooms(
-            connection_key.clone(),
-            list_id,
-            list_room_ids,
-            globalsince,
-        );
     }
 
-    let mut known_subscription_rooms = BTreeSet::new();
     for (room_id, room) in &body.room_subscriptions {
         if !services().rooms.metadata.exists(room_id)? {
             continue;
@@ -392,20 +383,14 @@ pub(crate) async fn sync_events_v4_route(
         todo_rooms.entry(room_id.clone()).or_default().update(
             room.required_state.clone(),
             room.timeline_limit.unwrap_or(uint!(10)),
-            known_rooms.get("subscriptions"),
+            &known_rooms,
             room_id,
         );
-        known_subscription_rooms.insert(room_id.clone());
-    }
-
-    for r in body.unsubscribe_rooms {
-        known_subscription_rooms.remove(&r);
     }
 
     services().users.update_sync_known_rooms(
         connection_key.clone(),
-        "subscriptions".to_owned(),
-        known_subscription_rooms,
+        todo_rooms.keys().cloned().collect(),
         globalsince,
     );
 
diff --git a/src/service/users.rs b/src/service/users.rs
index ab64130e..928843ae 100644
--- a/src/service/users.rs
+++ b/src/service/users.rs
@@ -21,7 +21,7 @@ pub(crate) use data::Data;
 
 #[derive(Debug, Default)]
 pub(crate) struct SlidingSyncCache {
-    known_rooms: BTreeMap<String, BTreeMap<OwnedRoomId, u64>>,
+    known_rooms: BTreeMap<OwnedRoomId, u64>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
@@ -69,7 +69,7 @@ impl Service {
     pub(crate) fn get_rooms_in_connection(
         &self,
         connection_key: ConnectionKey,
-    ) -> BTreeMap<String, BTreeMap<OwnedRoomId, u64>> {
+    ) -> BTreeMap<OwnedRoomId, u64> {
         let cached = self.get_cache_entry(connection_key);
         let cached = cached.lock().unwrap();
 
@@ -79,23 +79,14 @@ impl Service {
     pub(crate) fn update_sync_known_rooms(
         &self,
         connection_key: ConnectionKey,
-        list_id: String,
         new_cached_rooms: BTreeSet<OwnedRoomId>,
         globalsince: u64,
     ) {
         let cached = self.get_cache_entry(connection_key);
         let mut cached = cached.lock().unwrap();
 
-        for (roomid, lastsince) in
-            cached.known_rooms.entry(list_id.clone()).or_default().iter_mut()
-        {
-            if !new_cached_rooms.contains(roomid) {
-                *lastsince = 0;
-            }
-        }
-        let list = cached.known_rooms.entry(list_id).or_default();
         for roomid in new_cached_rooms {
-            list.insert(roomid, globalsince);
+            cached.known_rooms.insert(roomid, globalsince);
         }
     }