diff --git a/extensions/suspend/extend.php b/extensions/suspend/extend.php
index eba4ede5c..027417fbf 100644
--- a/extensions/suspend/extend.php
+++ b/extensions/suspend/extend.php
@@ -8,9 +8,11 @@
  */
 
 use Flarum\Api\Serializer\BasicUserSerializer;
+use Flarum\Api\Serializer\UserSerializer;
 use Flarum\Event\ConfigureUserGambits;
 use Flarum\Extend;
 use Flarum\Suspend\Access;
+use Flarum\Suspend\AddUserSuspendAttributes;
 use Flarum\Suspend\Event\Suspended;
 use Flarum\Suspend\Event\Unsuspended;
 use Flarum\Suspend\Listener;
@@ -33,6 +35,9 @@ return [
     (new Extend\Model(User::class))
         ->dateAttribute('suspended_until'),
 
+    (new Extend\ApiSerializer(UserSerializer::class))
+        ->mutate(AddUserSuspendAttributes::class),
+
     new Extend\Locales(__DIR__.'/locale'),
 
     (new Extend\Notification())
@@ -40,7 +45,6 @@ return [
         ->type(UserUnsuspendedBlueprint::class, BasicUserSerializer::class, ['alert', 'email']),
 
     function (Dispatcher $events) {
-        $events->subscribe(Listener\AddUserSuspendAttributes::class);
         $events->subscribe(Listener\RevokeAccessFromSuspendedUsers::class);
 
         $events->listen(Saving::class, Listener\SaveSuspensionToDatabase::class);
diff --git a/extensions/suspend/src/AddUserSuspendAttributes.php b/extensions/suspend/src/AddUserSuspendAttributes.php
new file mode 100755
index 000000000..9e694c1eb
--- /dev/null
+++ b/extensions/suspend/src/AddUserSuspendAttributes.php
@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Suspend;
+
+use Flarum\Api\Serializer\UserSerializer;
+use Flarum\User\User;
+
+class AddUserSuspendAttributes
+{
+    public function __invoke(UserSerializer $serializer, User $user)
+    {
+        $attributes = [];
+        $canSuspend = $serializer->getActor()->can('suspend', $user);
+
+        if ($canSuspend) {
+            $attributes['suspendedUntil'] = $serializer->formatDate($user->suspended_until);
+        }
+
+        $attributes['canSuspend'] = $canSuspend;
+
+        return $attributes;
+    }
+}
diff --git a/extensions/suspend/src/Listener/AddUserSuspendAttributes.php b/extensions/suspend/src/Listener/AddUserSuspendAttributes.php
deleted file mode 100755
index ada1fd4d2..000000000
--- a/extensions/suspend/src/Listener/AddUserSuspendAttributes.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php
-
-/*
- * This file is part of Flarum.
- *
- * For detailed copyright and license information, please view the
- * LICENSE file that was distributed with this source code.
- */
-
-namespace Flarum\Suspend\Listener;
-
-use Flarum\Api\Event\Serializing;
-use Flarum\Api\Serializer\UserSerializer;
-use Illuminate\Contracts\Events\Dispatcher;
-
-class AddUserSuspendAttributes
-{
-    /**
-     * @param Dispatcher $events
-     */
-    public function subscribe(Dispatcher $events)
-    {
-        $events->listen(Serializing::class, [$this, 'addAttributes']);
-    }
-
-    /**
-     * @param Serializing $event
-     */
-    public function addAttributes(Serializing $event)
-    {
-        if ($event->isSerializer(UserSerializer::class)) {
-            $canSuspend = $event->actor->can('suspend', $event->model);
-
-            if ($canSuspend) {
-                $event->attributes['suspendedUntil'] = $event->formatDate($event->model->suspended_until);
-            }
-
-            $event->attributes['canSuspend'] = $canSuspend;
-        }
-    }
-}