diff --git a/Debug/TraceableEventDispatcher.php b/Debug/TraceableEventDispatcher.php
index acfbf61..84d6a08 100644
--- a/Debug/TraceableEventDispatcher.php
+++ b/Debug/TraceableEventDispatcher.php
@@ -42,7 +42,7 @@ class TraceableEventDispatcher implements EventDispatcherInterface, ResetInterfa
     private $requestStack;
     private $currentRequestHash = '';
 
-    public function __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, LoggerInterface $logger = null, RequestStack $requestStack = null)
+    public function __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, ?LoggerInterface $logger = null, ?RequestStack $requestStack = null)
     {
         $this->dispatcher = $dispatcher;
         $this->stopwatch = $stopwatch;
@@ -97,7 +97,7 @@ public function removeSubscriber(EventSubscriberInterface $subscriber)
     /**
      * {@inheritdoc}
      */
-    public function getListeners(string $eventName = null)
+    public function getListeners(?string $eventName = null)
     {
         return $this->dispatcher->getListeners($eventName);
     }
@@ -123,7 +123,7 @@ public function getListenerPriority(string $eventName, $listener)
     /**
      * {@inheritdoc}
      */
-    public function hasListeners(string $eventName = null)
+    public function hasListeners(?string $eventName = null)
     {
         return $this->dispatcher->hasListeners($eventName);
     }
@@ -131,7 +131,7 @@ public function hasListeners(string $eventName = null)
     /**
      * {@inheritdoc}
      */
-    public function dispatch(object $event, string $eventName = null): object
+    public function dispatch(object $event, ?string $eventName = null): object
     {
         $eventName = $eventName ?? \get_class($event);
 
@@ -171,7 +171,7 @@ public function dispatch(object $event, string $eventName = null): object
     /**
      * @return array
      */
-    public function getCalledListeners(Request $request = null)
+    public function getCalledListeners(?Request $request = null)
     {
         if (null === $this->callStack) {
             return [];
@@ -192,7 +192,7 @@ public function getCalledListeners(Request $request = null)
     /**
      * @return array
      */
-    public function getNotCalledListeners(Request $request = null)
+    public function getNotCalledListeners(?Request $request = null)
     {
         try {
             $allListeners = $this->getListeners();
@@ -235,7 +235,7 @@ public function getNotCalledListeners(Request $request = null)
         return $notCalled;
     }
 
-    public function getOrphanedEvents(Request $request = null): array
+    public function getOrphanedEvents(?Request $request = null): array
     {
         if ($request) {
             return $this->orphanedEvents[spl_object_hash($request)] ?? [];
diff --git a/Debug/WrappedListener.php b/Debug/WrappedListener.php
index 3c4cc13..80d49a1 100644
--- a/Debug/WrappedListener.php
+++ b/Debug/WrappedListener.php
@@ -33,7 +33,7 @@ final class WrappedListener
     private $priority;
     private static $hasClassStub;
 
-    public function __construct($listener, ?string $name, Stopwatch $stopwatch, EventDispatcherInterface $dispatcher = null)
+    public function __construct($listener, ?string $name, Stopwatch $stopwatch, ?EventDispatcherInterface $dispatcher = null)
     {
         $this->listener = $listener;
         $this->optimizedListener = $listener instanceof \Closure ? $listener : (\is_callable($listener) ? \Closure::fromCallable($listener) : null);
diff --git a/EventDispatcher.php b/EventDispatcher.php
index 8fe8fb5..9c86bd9 100644
--- a/EventDispatcher.php
+++ b/EventDispatcher.php
@@ -45,7 +45,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function dispatch(object $event, string $eventName = null): object
+    public function dispatch(object $event, ?string $eventName = null): object
     {
         $eventName = $eventName ?? \get_class($event);
 
@@ -65,7 +65,7 @@ public function dispatch(object $event, string $eventName = null): object
     /**
      * {@inheritdoc}
      */
-    public function getListeners(string $eventName = null)
+    public function getListeners(?string $eventName = null)
     {
         if (null !== $eventName) {
             if (empty($this->listeners[$eventName])) {
@@ -120,7 +120,7 @@ public function getListenerPriority(string $eventName, $listener)
     /**
      * {@inheritdoc}
      */
-    public function hasListeners(string $eventName = null)
+    public function hasListeners(?string $eventName = null)
     {
         if (null !== $eventName) {
             return !empty($this->listeners[$eventName]);
diff --git a/EventDispatcherInterface.php b/EventDispatcherInterface.php
index cc324e1..4b65e5a 100644
--- a/EventDispatcherInterface.php
+++ b/EventDispatcherInterface.php
@@ -50,7 +50,7 @@ public function removeSubscriber(EventSubscriberInterface $subscriber);
      *
      * @return array<callable[]|callable>
      */
-    public function getListeners(string $eventName = null);
+    public function getListeners(?string $eventName = null);
 
     /**
      * Gets the listener priority for a specific event.
@@ -66,5 +66,5 @@ public function getListenerPriority(string $eventName, callable $listener);
      *
      * @return bool
      */
-    public function hasListeners(string $eventName = null);
+    public function hasListeners(?string $eventName = null);
 }
diff --git a/ImmutableEventDispatcher.php b/ImmutableEventDispatcher.php
index 568d79c..4e00bfa 100644
--- a/ImmutableEventDispatcher.php
+++ b/ImmutableEventDispatcher.php
@@ -28,7 +28,7 @@ public function __construct(EventDispatcherInterface $dispatcher)
     /**
      * {@inheritdoc}
      */
-    public function dispatch(object $event, string $eventName = null): object
+    public function dispatch(object $event, ?string $eventName = null): object
     {
         return $this->dispatcher->dispatch($event, $eventName);
     }
@@ -68,7 +68,7 @@ public function removeSubscriber(EventSubscriberInterface $subscriber)
     /**
      * {@inheritdoc}
      */
-    public function getListeners(string $eventName = null)
+    public function getListeners(?string $eventName = null)
     {
         return $this->dispatcher->getListeners($eventName);
     }
@@ -84,7 +84,7 @@ public function getListenerPriority(string $eventName, $listener)
     /**
      * {@inheritdoc}
      */
-    public function hasListeners(string $eventName = null)
+    public function hasListeners(?string $eventName = null)
     {
         return $this->dispatcher->hasListeners($eventName);
     }