diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1ad0d2e3..0169f689 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        PHP: [ '8.2', '8.3' ]
+        PHP: [ '8.2', '8.3', '8.4' ]
         TYPO3: [ '^13.4', '13.4.x-dev' ]
     env:
       typo3DatabaseName: 'typo3_ci'
diff --git a/Classes/Report/TikaStatus.php b/Classes/Report/TikaStatus.php
index 23411b6a..0f291603 100644
--- a/Classes/Report/TikaStatus.php
+++ b/Classes/Report/TikaStatus.php
@@ -53,7 +53,7 @@ class TikaStatus implements StatusProviderInterface
      * @throws ExtensionConfigurationPathDoesNotExistException
      */
     public function __construct(
-        array $extensionConfiguration = null,
+        ?array $extensionConfiguration = null,
     ) {
         $this->tikaConfiguration = $extensionConfiguration ?? Util::getTikaExtensionConfiguration();
     }
diff --git a/Classes/Service/Extractor/AbstractExtractor.php b/Classes/Service/Extractor/AbstractExtractor.php
index a1b31df1..511afda5 100644
--- a/Classes/Service/Extractor/AbstractExtractor.php
+++ b/Classes/Service/Extractor/AbstractExtractor.php
@@ -47,8 +47,10 @@ abstract class AbstractExtractor implements ExtractorInterface, LoggerAwareInter
      * @throws ExtensionConfigurationPathDoesNotExistException
      * @throws ExtensionConfigurationExtensionNotConfiguredException
      */
-    public function __construct(array $extensionConfiguration = null, SizeValidator $fileSizeValidator = null)
-    {
+    public function __construct(
+        ?array $extensionConfiguration = null,
+        ?SizeValidator $fileSizeValidator = null,
+    ) {
         $this->configuration = $extensionConfiguration ?? Util::getTikaExtensionConfiguration();
         $this->fileSizeValidator = $fileSizeValidator ?? GeneralUtility::makeInstance(
             SizeValidator::class,
diff --git a/Classes/Service/File/SizeValidator.php b/Classes/Service/File/SizeValidator.php
index 905c7487..ac48e313 100644
--- a/Classes/Service/File/SizeValidator.php
+++ b/Classes/Service/File/SizeValidator.php
@@ -35,8 +35,9 @@ class SizeValidator
      * @throws ExtensionConfigurationExtensionNotConfiguredException
      * @throws ExtensionConfigurationPathDoesNotExistException
      */
-    public function __construct(array $extensionConfiguration = null)
-    {
+    public function __construct(
+        ?array $extensionConfiguration = null,
+    ) {
         $this->configuration = $extensionConfiguration ?? Util::getTikaExtensionConfiguration();
     }
 
diff --git a/Classes/Service/Tika/ServiceFactory.php b/Classes/Service/Tika/ServiceFactory.php
index 8fc4b8f6..b1a56ef6 100644
--- a/Classes/Service/Tika/ServiceFactory.php
+++ b/Classes/Service/Tika/ServiceFactory.php
@@ -39,7 +39,7 @@ class ServiceFactory
      */
     public static function getTika(
         string $tikaServiceType,
-        array $configuration = null,
+        ?array $configuration = null,
     ): ServerService|AppService|SolrCellService {
         if (empty($configuration)) {
             $configuration = Util::getTikaExtensionConfiguration();
diff --git a/Tests/Integration/Service/Tika/ServiceIntegrationTestCase.php b/Tests/Integration/Service/Tika/ServiceIntegrationTestCase.php
index ef3ec587..cefb4f72 100644
--- a/Tests/Integration/Service/Tika/ServiceIntegrationTestCase.php
+++ b/Tests/Integration/Service/Tika/ServiceIntegrationTestCase.php
@@ -280,8 +280,8 @@ protected function getConfiguration(): array
 
     protected function getMockedFileInstance(
         array $fileData,
-        ResourceStorage $storage = null,
-        array $metaData = []
+        ?ResourceStorage $storage = null,
+        array $metaData = [],
     ): File|MockObject {
         $fileMock = $this->getMockBuilder(File::class)
             ->setConstructorArgs([
diff --git a/Tests/Unit/ExecMockFunctions.php.Hack b/Tests/Unit/ExecMockFunctions.php.Hack
index 6e46ce8a..647376e7 100644
--- a/Tests/Unit/ExecMockFunctions.php.Hack
+++ b/Tests/Unit/ExecMockFunctions.php.Hack
@@ -29,8 +29,11 @@ use ApacheSolrForTypo3\Tika\Tests\Unit\ExecRecorder;
  * exec() mock to capture invocation parameters for the actual \exec() function
  * @noinspection PhpUnusedParameterInspection
  */
-function exec(string $command, array &$output = null, int &$result_code = null): string|false
-{
+function exec(
+    string $command,
+    ?array &$output = null,
+    ?int &$result_code = null,
+): string|false {
     $output = array_key_exists(ExecRecorder::$execCalled, ExecRecorder::$execOutput) ? ExecRecorder::$execOutput[ExecRecorder::$execCalled] : '';
     ExecRecorder::$execCalled++;
     ExecRecorder::$execCommand = $command;