diff --git a/features/demo_app/src/DefaultKernel.php b/features/demo_app/src/DefaultKernel.php
index cc9494e..8d505a1 100644
--- a/features/demo_app/src/DefaultKernel.php
+++ b/features/demo_app/src/DefaultKernel.php
@@ -7,7 +7,7 @@
 
 class DefaultKernel extends AbstractKernel
 {
-    public function registerBundles()
+    public function registerBundles(): iterable
     {
         /** @noinspection PhpIncludeInspection */
         $contents = require $this->getProjectDir().'/'.$this->getConfigDirectory().'/bundles.php';