1 files changed, 1 insertions, 1 deletions
diff --git a/matrix-specification/Data/Room/UnreadNotificationCounts.php b/matrix-specification/Data/Room/UnreadNotificationCounts.php
index d2600e6..f00a6a5 100644
--- a/matrix-specification/Data/Room/UnreadNotificationCounts.php
+++ b/matrix-specification/Data/Room/UnreadNotificationCounts.php
@@ -15,6 +15,6 @@ class UnreadNotificationCounts implements \JsonSerializable
     return array_filter([
       "highlight_count" => $this->highlightCount,
       "notification_count" => $this->notificationCount,
-    ], "is_null");
+    ], fn ($value) => ! is_null($value));
   }
 }