diff --git a/src/mibew/libs/classes/Mibew/Controller/Group/AbstractController.php b/src/mibew/libs/classes/Mibew/Controller/Group/AbstractController.php
index 1fab3a81..dea909a4 100644
--- a/src/mibew/libs/classes/Mibew/Controller/Group/AbstractController.php
+++ b/src/mibew/libs/classes/Mibew/Controller/Group/AbstractController.php
@@ -23,7 +23,7 @@ use Symfony\Component\HttpFoundation\Request;
 /**
  * Provides a set of utility functions.
  */
-class AbstractController extends BaseController
+abstract class AbstractController extends BaseController
 {
     /**
      * Builds list of the group tabs.