diff --git a/Controller/BackendController.php b/Controller/BackendController.php
index 7decfe9..58f82eb 100755
--- a/Controller/BackendController.php
+++ b/Controller/BackendController.php
@@ -42,7 +42,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageInbox(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageInbox(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-dashboard');
@@ -63,7 +63,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageOutbox(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageOutbox(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-out-view');
@@ -84,7 +84,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageTrash(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageTrash(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-trash-view');
@@ -105,7 +105,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageSpam(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageSpam(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-spam-view');
@@ -126,7 +126,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageView(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageView(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-view');
@@ -148,7 +148,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageCreate(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageCreate(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/mail-create');
@@ -169,7 +169,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewMessageSettings(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewMessageSettings(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Messages/Theme/Backend/message-settings');