diff --git a/src/Database/ModelTraits/UserPermanentlyDeletable.php b/src/Database/ModelTraits/UserPermanentlyDeletable.php
index 3ab6bab..f8c7e9a 100644
--- a/src/Database/ModelTraits/UserPermanentlyDeletable.php
+++ b/src/Database/ModelTraits/UserPermanentlyDeletable.php
@@ -29,7 +29,7 @@ trait UserPermanentlyDeletable {
         return true;
     }
 
-    public function bootUserPermanentlyDeletable()
+    static public function bootUserPermanentlyDeletable()
     {
         static::deleting(function ($user) {
             if (!$user->preventActivityPurge()) {