diff --git a/src/MissingNextcloudUsernameException.php b/src/MissingNextcloudUsernameException.php
index de5f5fa..d9c2974 100644
--- a/src/MissingNextcloudUsernameException.php
+++ b/src/MissingNextcloudUsernameException.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Nino\FilesystemProviders;
 
 class MissingNextcloudUsernameException extends \Exception