diff --git a/.github/workflows/quality-assurance.yaml b/.github/workflows/quality-assurance.yaml
index 1823586..f1d7b38 100644
--- a/.github/workflows/quality-assurance.yaml
+++ b/.github/workflows/quality-assurance.yaml
@@ -17,6 +17,18 @@ jobs:
           - php: '8.0'
             composer-flags: '--ignore-platform-req=php'
             phpunit-flags: '--no-coverage'
+          - php: '8.1'
+            composer-flags: '--ignore-platform-req=php'
+            phpunit-flags: '--no-coverage'
+          - php: '8.2'
+            composer-flags: '--ignore-platform-req=php'
+            phpunit-flags: '--no-coverage'
+          - php: '8.3'
+            composer-flags: '--ignore-platform-req=php'
+            phpunit-flags: '--no-coverage'
+          - php: '8.4'
+            composer-flags: '--ignore-platform-req=php'
+            phpunit-flags: '--no-coverage'
           - php: '7.2'
             composer-flags: '--prefer-lowest'
             phpunit-flags: '--no-coverage'
diff --git a/src/EventDispatcher.php b/src/EventDispatcher.php
index 6c5128f..35fdaea 100644
--- a/src/EventDispatcher.php
+++ b/src/EventDispatcher.php
@@ -14,7 +14,7 @@ class EventDispatcher implements EventDispatchingListenerRegistry
      */
     protected $listenerProvider;
 
-    public function __construct(ListenerProviderInterface $listenerProvider = null)
+    public function __construct(?ListenerProviderInterface $listenerProvider = null)
     {
         $this->listenerProvider = $listenerProvider instanceof ListenerProviderInterface
             ? $listenerProvider