diff --git a/Controller/BackendController.php b/Controller/BackendController.php
index 2c5b3ad..90d47f6 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 viewPurchaseInvoiceList(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseInvoiceList(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/invoice-list');
@@ -63,7 +63,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewPurchaseInvoiceCreate(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseInvoiceCreate(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/invoice-create');
@@ -84,7 +84,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewPurchaseArticleList(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseArticleList(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/article-list');
@@ -105,7 +105,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewPurchaseArticleCreate(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseArticleCreate(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/article-create');
@@ -126,7 +126,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewPurchaseArticleProfile(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseArticleProfile(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/article-profile');
@@ -147,7 +147,7 @@ final class BackendController extends Controller
      * @since 1.0.0
      * @codeCoverageIgnore
      */
-    public function viewPurchaseOrderSuggestion(RequestAbstract $request, ResponseAbstract $response, $data = null) : RenderableInterface
+    public function viewPurchaseOrderSuggestion(RequestAbstract $request, ResponseAbstract $response, mixed $data = null) : RenderableInterface
     {
         $view = new View($this->app->l11nManager, $request, $response);
         $view->setTemplate('/Modules/Purchase/Theme/Backend/article-order-recommendation');