diff --git a/plugins/ActivityPub/ActivityPub.php b/plugins/ActivityPub/ActivityPub.php
index 47131f1931..fb7871ff6e 100644
--- a/plugins/ActivityPub/ActivityPub.php
+++ b/plugins/ActivityPub/ActivityPub.php
@@ -70,6 +70,7 @@ use function count;
 use function is_null;
 use const PHP_URL_HOST;
 use const PREG_SET_ORDER;
+use InvalidArgumentException;
 
 /**
  * Adds ActivityPub support to GNU social when enabled
@@ -115,13 +116,13 @@ class ActivityPub extends Plugin
             'activitypub_inbox',
             '/inbox.json',
             [Inbox::class, 'handle'],
-            options: ['accept' => self::$accept_headers, 'format' => self::$accept_headers[0]],
+            options: ['format' => self::$accept_headers[0]],
         );
         $r->connect(
             'activitypub_actor_inbox',
             '/actor/{gsactor_id<\d+>}/inbox.json',
             [Inbox::class, 'handle'],
-            options: ['accept' => self::$accept_headers, 'format' => self::$accept_headers[0]],
+            options: ['format' => self::$accept_headers[0]],
         );
         $r->connect(
             'activitypub_actor_outbox',
@@ -140,7 +141,7 @@ class ActivityPub extends Plugin
      * @param string|null $url
      * @return bool
      */
-    public function onStartGetActorUrl(Actor $actor, int $type, ?string &$url): bool
+    public function onStartGetActorUri(Actor $actor, int $type, ?string &$url): bool
     {
         if (
             // Is remote?
@@ -384,6 +385,34 @@ class ActivityPub extends Plugin
         }
     }
 
+    /**
+     * @param mixed $object
+     * @return string got from URI
+     */
+    public static function getUriByObject(mixed $object): string
+    {
+        if ($object instanceof Note) {
+            if($object->getIsLocal()) {
+                return $object->getUrl();
+            } else {
+                // Try known remote objects
+                $known_object = ActivitypubObject::getByPK(['object_type' => 'note', 'object_id' => $object->getId()]);
+                if ($known_object instanceof ActivitypubObject) {
+                    return $known_object->getObjectUri();
+                }
+            }
+        } else if ($object instanceof Activity) {
+			// Try known remote activities
+			$known_activity = ActivitypubActivity::getByPK(['activity_id' => $object->getId()]);
+			if ($known_activity instanceof ActivitypubActivity) {
+				return $known_activity->getActivityUri();
+			} else {
+                return Router::url('activity_view', ['id' => $object->getId()], Router::ABSOLUTE_URL);
+            }
+		}
+        throw new InvalidArgumentException('ActivityPub::getUriByObject found a limitation with: '.var_export($object, true));
+    }
+
     /**
      * Get a Note from ActivityPub URI, if it doesn't exist, attempt to fetch it
      * This should only be necessary internally.
diff --git a/plugins/ActivityPub/Util/Model/Activity.php b/plugins/ActivityPub/Util/Model/Activity.php
index 90917e4577..f5ce715a94 100644
--- a/plugins/ActivityPub/Util/Model/Activity.php
+++ b/plugins/ActivityPub/Util/Model/Activity.php
@@ -151,25 +151,29 @@ class Activity extends Model
         if ($object::class !== 'App\Entity\Activity') {
             throw new InvalidArgumentException('First argument type is Activity');
         }
-
-        $gs_verb_to_activity_stream_two_verb = fn($verb): string => match ($verb) {
-            'create' => 'Create',
-            default => throw new ClientException('Invalid verb'),
-        };
+        
+		$gs_verb_to_activity_stream_two_verb = null;
+		if (Event::handle('GSVerbToActivityStreamsTwoActivityType', [($verb = $object->getVerb()), &$gs_verb_to_activity_stream_two_verb]) === Event::next) {
+			$gs_verb_to_activity_stream_two_verb = match ($verb) {
+				'create' => 'Create',
+				'undo' => 'Undo',
+				default => throw new ClientException('Invalid verb'),
+			};
+		}
 
         $attr = [
-            'type' => $gs_verb_to_activity_stream_two_verb($object->getVerb()),
+            'type' => $gs_verb_to_activity_stream_two_verb,
             '@context' => 'https://www.w3.org/ns/activitystreams',
             'id' => Router::url('activity_view', ['id' => $object->getId()], Router::ABSOLUTE_URL),
             'published' => $object->getCreated()->format(DateTimeInterface::RFC3339),
             'actor' => $object->getActor()->getUri(Router::ABSOLUTE_URL),
             'to' => ['https://www.w3.org/ns/activitystreams#Public'], // TODO: implement proper scope address
             'cc' => ['https://www.w3.org/ns/activitystreams#Public'],
-            'object' => self::jsonToType(self::toJson($object->getObject())),
         ];
+        $attr['object'] = $attr['type'] === 'Create' ? self::jsonToType(Model::toJson($object->getObject())) : ActivityPub::getUriByObject($object->getObject());
 
         $type = self::jsonToType($attr);
         Event::handle('ActivityPubAddActivityStreamsTwoData', [$type->get('type'), &$type]);
         return $type->toJson($options);
     }
-}
\ No newline at end of file
+}