diff --git a/src/User/NotificationPreference.php b/src/User/NotificationPreference.php
index 57e146549..5b042c1e8 100644
--- a/src/User/NotificationPreference.php
+++ b/src/User/NotificationPreference.php
@@ -23,7 +23,7 @@ use InvalidArgumentException;
  */
 class NotificationPreference extends AbstractModel
 {
-    static protected $channels = [];
+    protected static $channels = [];
 
     public function user()
     {