diff --git a/events/handlers/ap_delivery_handler.py b/events/handlers/ap_delivery_handler.py
index c9fb5d9..4d40ef3 100644
--- a/events/handlers/ap_delivery_handler.py
+++ b/events/handlers/ap_delivery_handler.py
@@ -42,6 +42,9 @@ def _build_activity_json(activity: APActivity, actor: ActorProfile, domain: str)
         obj.setdefault("published", activity.published.isoformat() if activity.published else None)
         obj.setdefault("to", ["https://www.w3.org/ns/activitystreams#Public"])
         obj.setdefault("cc", [f"{actor_url}/followers"])
+        if activity.activity_type == "Update":
+            from datetime import datetime, timezone
+            obj["updated"] = datetime.now(timezone.utc).isoformat()
 
     return {
         "@context": [