diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27447c29..24a0a5b0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,6 +47,8 @@ jobs:
 
       - name: Check coding style
         run: composer lint
+        with:
+          php-version: 8.1
 
       - name: Run Unit Tests
         run: |
diff --git a/Classes/Controller/SearchController.php b/Classes/Controller/SearchController.php
index b0f879eb..80d303ee 100644
--- a/Classes/Controller/SearchController.php
+++ b/Classes/Controller/SearchController.php
@@ -43,8 +43,6 @@
 
 class SearchController extends ActionController
 {
-    public $response;
-
     protected array $requestArguments = [];
 
     protected ?object $searchProvider = null;
@@ -64,17 +62,15 @@ public function detailAction(string $id): ResponseInterface
     {
         $arguments = $this->searchProvider->getRequestArguments();
         $detail = $this->searchProvider->getDocumentById($id);
-
+        $response = $this->responseFactory->createResponse();
         if ($this->request->hasArgument('underlyingQuery')) {
             $underlyingQueryInfo = $this->request->getArgument('underlyingQuery');
-            $this->response->addAdditionalHeaderData(
-                FrontendUtility::addQueryInformationAsJavaScript(
-                    $underlyingQueryInfo['q'],
-                    $this->settings,
-                    (int) $underlyingQueryInfo['position'],
-                    $arguments
-                )
-            );
+            $response->withAddedHeader('detail', FrontendUtility::addQueryInformationAsJavaScript(
+                $underlyingQueryInfo['q'],
+                $this->settings,
+                (int) $underlyingQueryInfo['position'],
+                $arguments
+            ));
         }
 
         $this->addStandardAssignments();
@@ -95,36 +91,38 @@ public function indexAction(): ResponseInterface
     {
         if (array_key_exists('id', $this->requestArguments)) {
             return new ForwardResponse('detail');
-        } else {
-            $this->searchProvider->setCounter();
-            $this->response->addAdditionalHeaderData(
-                FrontendUtility::addQueryInformationAsJavaScript(
-                    $this->searchProvider->getRequestArguments()['q'],
-                    $this->settings,
-                    null,
-                    $this->searchProvider->getRequestArguments()
-                )
-            );
-
-            $this->addStandardAssignments();
-            $defaultQuery = $this->searchProvider->getDefaultQuery();
-
-            $viewValues = [
-                'arguments' => $this->searchProvider->getRequestArguments(),
-                'config' => $this->searchProvider->getConfiguration(),
-            ];
-
-            CoreArrayUtility::mergeRecursiveWithOverrule($viewValues, $defaultQuery);
-            $this->view->assignMultiple($viewValues);
         }
 
+        $this->searchProvider->setCounter();
+        $response = $this->responseFactory->createResponse();
+
+        $response->withAddedHeader('index',
+            FrontendUtility::addQueryInformationAsJavaScript(
+                $this->searchProvider->getRequestArguments()['q'],
+                $this->settings,
+                null,
+                $this->searchProvider->getRequestArguments()
+            )
+        );
+
+        $this->addStandardAssignments();
+        $defaultQuery = $this->searchProvider->getDefaultQuery();
+
+        $viewValues = [
+            'arguments' => $this->searchProvider->getRequestArguments(),
+            'config' => $this->searchProvider->getConfiguration(),
+        ];
+
+        CoreArrayUtility::mergeRecursiveWithOverrule($viewValues, $defaultQuery);
+        $this->view->assignMultiple($viewValues);
+
         return $this->htmlResponse();
     }
 
     /**
      * Initialisation and setup.
      */
-    protected function initializeAction()
+    protected function initializeAction(): void
     {
         ksort($this->settings['queryFields']);
 
@@ -152,7 +150,7 @@ public function suggestAction(): ResponseInterface
     /**
      * Assigns standard variables to the view.
      */
-    protected function addStandardAssignments()
+    protected function addStandardAssignments(): void
     {
         $this->searchProvider->setConfigurationValue('extendedSearch', $this->searchProvider->isExtendedSearch());
         $this->searchProvider->setConfigurationValue(
@@ -166,7 +164,7 @@ protected function addStandardAssignments()
     /**
      * @param string $activeConnection
      */
-    protected function initializeConnection($activeConnection)
+    protected function initializeConnection($activeConnection): void
     {
         $connectionConfiguration = $this->settings['connections'][$activeConnection];
 
diff --git a/Tests/Unit/ViewHelpers/Find/PathExistsViewHelperTest.php b/Tests/Unit/ViewHelpers/Find/PathExistsViewHelperTest.php
index 00d1b292..c075b691 100644
--- a/Tests/Unit/ViewHelpers/Find/PathExistsViewHelperTest.php
+++ b/Tests/Unit/ViewHelpers/Find/PathExistsViewHelperTest.php
@@ -49,7 +49,7 @@ protected function setUp(): void
     /**
      * @test
      */
-    public function returnFalseIfAPathDoesNotExist()
+    public function returnFalseIfAPathDoesNotExist(): void
     {
         $this->fixture->setArguments(
             [
@@ -63,7 +63,7 @@ public function returnFalseIfAPathDoesNotExist()
     /**
      * @test
      */
-    public function returnTrueIfAPathExists()
+    public function returnTrueIfAPathExists(): void
     {
         $this->fixture->setArguments(
             [