diff --git a/changelog.d/5884.feature b/changelog.d/5884.feature
new file mode 100644
index 000000000..bfd048939
--- /dev/null
+++ b/changelog.d/5884.feature
@@ -0,0 +1 @@
+Enable cleaning up extremities with dummy events by default to prevent undue build up of forward extremities.
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 419787a89..3a7a49bc9 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -355,10 +355,8 @@ class ServerConfig(Config):
 
         _check_resource_config(self.listeners)
 
-        # An experimental option to try and periodically clean up extremities
-        # by sending dummy events.
         self.cleanup_extremities_with_dummy_events = config.get(
-            "cleanup_extremities_with_dummy_events", False
+            "cleanup_extremities_with_dummy_events", True
         )
 
     def has_tls_listener(self):