diff --git a/src/matrix/room/timeline/EventKey.ts b/src/matrix/room/timeline/EventKey.ts
index 8775df26..8f1e17da 100644
--- a/src/matrix/room/timeline/EventKey.ts
+++ b/src/matrix/room/timeline/EventKey.ts
@@ -25,11 +25,6 @@ export class EventKey {
     ) {
     }
 
-    nextFragmentKey(): EventKey {
-        // could take MIN_EVENT_INDEX here if it can't be paged back
-        return new EventKey(this.fragmentId + 1, KeyLimits.middleStorageKey);
-    }
-
     nextKeyForDirection(direction: Direction): EventKey {
         if (direction.isForward) {
             return this.nextKey();
diff --git a/src/matrix/room/timeline/persistence/SyncWriter.js b/src/matrix/room/timeline/persistence/SyncWriter.js
index 1ee2ce7d..8fd9d16a 100644
--- a/src/matrix/room/timeline/persistence/SyncWriter.js
+++ b/src/matrix/room/timeline/persistence/SyncWriter.js
@@ -124,7 +124,8 @@ export class SyncWriter {
         } else if (timeline.limited) {
             // replace live fragment for limited sync, *only* if we had a live fragment already
             const oldFragmentId = currentKey.fragmentId;
-            currentKey = currentKey.nextFragmentKey();
+            const maxFragmentId = await txn.timelineFragments.getMaxFragmentId(this._roomId);
+            currentKey = EventKey.defaultFragmentKey(maxFragmentId + 1);
             const {oldFragment, newFragment} = await this._replaceLiveFragment(oldFragmentId, currentKey.fragmentId, timeline.prev_batch, txn);
             entries.push(FragmentBoundaryEntry.end(oldFragment, this._fragmentIdComparer));
             entries.push(FragmentBoundaryEntry.start(newFragment, this._fragmentIdComparer));