Fixup

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py

index 98a9b5a842..e57fe4c61f 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -988,7 +988,7 @@ class SlidingSyncRestServlet(RestServlet):
         serialized_rooms: Dict[str, JsonDict] = {}
         for room_id, room_result in rooms.items():
             serialized_rooms[room_id] = {
-                "bump_stamp": room_result.bump_stamp,
+                "bump_stamp": abs(room_result.bump_stamp),
                 "timestamp": abs(room_result.bump_stamp),
                 "joined_count": room_result.joined_count,
                 "invited_count": room_result.invited_count,