diff --git a/message_notify.module b/message_notify.module
index 41b04b7..55ab5e7 100644
--- a/message_notify.module
+++ b/message_notify.module
@@ -77,7 +77,7 @@ function message_notify_entity_info_alter(&$entity_info) {
     foreach ($view_modes as &$view_mode) {
       $view_mode += array('custom settings' => TRUE);
     }
-    $entity_info['message']['view modes'] += $view_modes;
+    $entity_info['message']['view modes'] = array_merge($entity_info['message']['view modes'], (array) $view_modes);
   }
 }