diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index d40218dd2..84a039489 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -804,6 +804,7 @@ class PresenceEventSource(object):
             )
 
     @defer.inlineCallbacks
+    @log_function
     def get_new_events_for_user(self, user, from_key, limit):
         from_key = int(from_key)
 
@@ -816,7 +817,8 @@ class PresenceEventSource(object):
         # TODO(paul): use a DeferredList ? How to limit concurrency.
         for observed_user in cachemap.keys():
             cached = cachemap[observed_user]
-            if not (from_key < cached.serial):
+
+            if cached.serial <= from_key:
                 continue
 
             if (yield self.is_visible(observer_user, observed_user)):