diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 3919da135e..2aefe062f7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -5,6 +5,7 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "main" ]
+  workflow_dispatch:
 
 jobs:
   test:
@@ -12,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        variants: [ {typo3: 11.5, php: 8.1}, {typo3: 12.4, php: 8.1} ]
+        variants: [ {typo3: 11.5, php: 8.1}, {typo3: 12.4, php: 8.1}, {typo3: 12.4, php: 8.4}  ]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
diff --git a/Build/Test/runTests.sh b/Build/Test/runTests.sh
index f7d8a27f4f..2103ed0f5b 100755
--- a/Build/Test/runTests.sh
+++ b/Build/Test/runTests.sh
@@ -113,11 +113,12 @@ Options:
             - 5.7
             - 8.0 (default)
 
-    -p <8.1|8.2|8.3>
+    -p <8.1|8.2|8.3|8.4>
         Specifies the PHP minor version to be used
             - 8.1: use PHP 8.1 (default)
             - 8.2: use PHP 8.2
             - 8.3: use PHP 8.3
+            - 8.4: use PHP 8.4
 
     -e "<phpunit options>"
         Only with -s functional|functionalDeprecated|unit|unitDeprecated|unitRandom|acceptance
@@ -218,7 +219,7 @@ while getopts ":a:s:t:d:i:j:p:e:xy:whuv" OPT; do
             ;;
         p)
             PHP_VERSION=${OPTARG}
-            if ! [[ ${PHP_VERSION} =~ ^(8.1|8.2|8.3)$ ]]; then
+            if ! [[ ${PHP_VERSION} =~ ^(8.1|8.2|8.3|8.4)$ ]]; then
                 INVALID_OPTIONS+=("${OPTARG}")
             fi
             ;;
diff --git a/Classes/Controller/PageViewController.php b/Classes/Controller/PageViewController.php
index 51debb509f..a27e154f77 100644
--- a/Classes/Controller/PageViewController.php
+++ b/Classes/Controller/PageViewController.php
@@ -312,7 +312,7 @@ public function addDocumentAction(FormAddDocument $formAddDocument): ResponseInt
      * @param int|null $docNumber
      * @return array
      */
-    protected function getMeasures(int $page, MetsDocument $specificDoc = null, $docNumber = null): array
+    protected function getMeasures(int $page, ?MetsDocument $specificDoc = null, $docNumber = null): array
     {
         if ($specificDoc) {
             $doc = $specificDoc;
@@ -380,7 +380,7 @@ protected function getMeasures(int $page, MetsDocument $specificDoc = null, $doc
      *
      * @return array URL and MIME type of fulltext file
      */
-    protected function getScore(int $page, MetsDocument $specificDoc = null)
+    protected function getScore(int $page, ?MetsDocument $specificDoc = null)
     {
         $score = [];
         $loc = '';
@@ -638,7 +638,7 @@ protected function getAnnotationContainers(int $page): array
      *
      * @return array URL and MIME type of image file
      */
-    protected function getImage(int $page, MetsDocument $specificDoc = null): array
+    protected function getImage(int $page, ?MetsDocument $specificDoc = null): array
     {
         $image = [];
         // Get @USE value of METS fileGrp.
diff --git a/composer.json b/composer.json
index 1458d46451..0c7a492343 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
     "docs": "https://docs.typo3.org/p/kitodo/presentation/main/en-us/"
   },
   "require": {
-    "php": "8.1 - 8.3",
+    "php": "8.1 - 8.4",
     "ext-curl": "*",
     "ext-dom": "*",
     "ext-json": "*",
diff --git a/ext_emconf.php b/ext_emconf.php
index 47021d2326..bee546beac 100644
--- a/ext_emconf.php
+++ b/ext_emconf.php
@@ -17,7 +17,7 @@
     'category' => 'misc',
     'constraints' => [
         'depends' => [
-            'php' => '8.1.0-8.3.99',
+            'php' => '8.1.0-8.4.99',
             'typo3' => '11.5.0-12.4.99'
         ],
         'conflicts' => [],