diff --git a/plugins/ActivityPub/classes/Activitypub_profile.php b/plugins/ActivityPub/classes/Activitypub_profile.php
index d576d13e69..ee1aedeac8 100644
--- a/plugins/ActivityPub/classes/Activitypub_profile.php
+++ b/plugins/ActivityPub/classes/Activitypub_profile.php
@@ -489,7 +489,7 @@ class Activitypub_profile extends Managed_DataObject
      * @throws NoProfileException
      * @author Diogo Cordeiro <diogo@fc.up.pt>
      */
-    public static function update_profile(Activitypub_profile $aprofile, array $res): Profile
+    public static function update_profile(Activitypub_profile $aprofile, $res): Profile
     {
         if ($res === false) {
             $profile = $aprofile->local_profile();
@@ -498,6 +498,10 @@ class Activitypub_profile extends Managed_DataObject
             throw new NoProfileException($id, "410 Gone");
         }
 
+        if (!is_array($res)) {
+            throw new InvalidArgumentException('TypeError: Argument 2 passed to Activitypub_profile::update_profile() must be of the type array or bool(false).');
+        }
+
         // ActivityPub Profile
         $aprofile->uri = $res['id'];
         $aprofile->nickname = $res['preferredUsername'];