diff --git a/Controller/ApiController.php b/Controller/ApiController.php
index 3234382..680d17a 100644
--- a/Controller/ApiController.php
+++ b/Controller/ApiController.php
@@ -40,7 +40,7 @@ final class ApiController extends Controller
      *
      * @param RequestAbstract  $request  Request
      * @param ResponseAbstract $response Response
-     * @param mixed            $data     Generic data
+     * @param array            $data     Generic data
      *
      * @return void
      *
@@ -48,7 +48,7 @@ final class ApiController extends Controller
      *
      * @since 1.0.0
      */
-    public function apiLabelLayoutCreate(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : void
+    public function apiLabelLayoutCreate(RequestAbstract $request, ResponseAbstract $response, array $data = []) : void
     {
         if (!empty($val = $this->validateLabelLayoutCreate($request))) {
             $response->header->status = RequestStatusCode::R_400;
@@ -143,7 +143,7 @@ final class ApiController extends Controller
      *
      * @param RequestAbstract  $request  Request
      * @param ResponseAbstract $response Response
-     * @param mixed            $data     Generic data
+     * @param array            $data     Generic data
      *
      * @return void
      *
@@ -151,7 +151,7 @@ final class ApiController extends Controller
      *
      * @since 1.0.0
      */
-    public function apiLabelLayoutL11nCreate(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : void
+    public function apiLabelLayoutL11nCreate(RequestAbstract $request, ResponseAbstract $response, array $data = []) : void
     {
         if (!empty($val = $this->validateLabelLayoutL11nCreate($request))) {
             $response->header->status = RequestStatusCode::R_400;
diff --git a/Controller/BackendController.php b/Controller/BackendController.php
index ca8bc3b..42dadf6 100644
--- a/Controller/BackendController.php
+++ b/Controller/BackendController.php
@@ -36,14 +36,14 @@ final class BackendController extends Controller
      *
      * @param RequestAbstract  $request  Request
      * @param ResponseAbstract $response Response
-     * @param mixed            $data     Generic data
+     * @param array            $data     Generic data
      *
      * @return RenderableInterface
      *
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewItemLabelList(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
+    public function viewItemLabelList(RequestAbstract $request, ResponseAbstract $response, array $data = []) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Labeling/Theme/Backend/layout-list');
@@ -67,14 +67,14 @@ final class BackendController extends Controller
      *
      * @param RequestAbstract  $request  Request
      * @param ResponseAbstract $response Response
-     * @param mixed            $data     Generic data
+     * @param array            $data     Generic data
      *
      * @return RenderableInterface
      *
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewItemList(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
+    public function viewItemList(RequestAbstract $request, ResponseAbstract $response, array $data = []) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Labeling/Theme/Backend/item-list');
@@ -102,14 +102,14 @@ final class BackendController extends Controller
      *
      * @param RequestAbstract  $request  Request
      * @param ResponseAbstract $response Response
-     * @param mixed            $data     Generic data
+     * @param array            $data     Generic data
      *
      * @return RenderableInterface
      *
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewItem(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
+    public function viewItem(RequestAbstract $request, ResponseAbstract $response, array $data = []) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Labeling/Theme/Backend/layout-item');