diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3422c1d4..b238c4df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ Latest
 ## Fixes
 * [#192](https://github.com/cleverage/process-bundle/issues/192) Fix CommandRunnerTask: only pass the `options` option to `Process::setOptions()`, support string `commandline` through `Process::fromShellCommandline()`, validate option types. Update documentation, add tests.
 * [#194](https://github.com/cleverage/process-bundle/issues/194) Fix ProcessLauncherTask: the `process_options` normalizer returned an array despite its scalar return type, so the task always failed with a `TypeError`. Update documentation, add tests.
+* [#189](https://github.com/cleverage/process-bundle/issues/189) Fix EventDispatcherTask: dispatch the event under the `event_name` option (regression since v4.0). `event_name` is now optional: when `null` (default), the event is dispatched under its class name. Update documentation.
 
 v5.0
 -----
diff --git a/docs/reference/tasks/event_dispatcher_task.md b/docs/reference/tasks/event_dispatcher_task.md
index 23ac3f98..0a0479f9 100644
--- a/docs/reference/tasks/event_dispatcher_task.md
+++ b/docs/reference/tasks/event_dispatcher_task.md
@@ -24,10 +24,10 @@ Possible outputs
 Options
 -------
 
-| Code         | Type     | Required | Default | Description                                                   |
-|--------------|----------|:--------:|---------|---------------------------------------------------------------|
-| `event_name` | `string` |  **X**   |         | Name of the event (see Notes: currently not used to dispatch) |
-| `passive`    | `bool`   |          | `true`  | If `true`, the input is passed to the output before dispatch  |
+| Code         | Type           | Required | Default | Description                                                                |
+|--------------|----------------|:--------:|---------|----------------------------------------------------------------------------|
+| `event_name` | `string\|null` |          | `null`  | Name of the dispatched event, `null` to use the event class name (see Notes) |
+| `passive`    | `bool`         |          | `true`  | If `true`, the input is passed to the output before dispatch               |
 
 Examples
 --------
@@ -50,6 +50,18 @@ push_data_event:
 Notes
 -----
 
-The event is dispatched without an explicit name (`$eventDispatcher->dispatch($event)`), so its name is the event
-class name. Listeners must therefore subscribe to `CleverAge\ProcessBundle\Event\EventDispatcherTaskEvent`; the
-`event_name` option is required and validated but not used for dispatching.
+The event is dispatched with `$eventDispatcher->dispatch($event, $eventName)`:
+
+* when `event_name` is set, listeners must subscribe to that name:
+
+```php
+#[AsEventListener(event: 'myapp.data_queue')]
+public function onDataQueue(EventDispatcherTaskEvent $event): void
+{
+    $input = $event->getState()->getInput();
+}
+```
+
+* when `event_name` is `null`, the event name is the event class name, so listeners must subscribe to
+  `CleverAge\ProcessBundle\Event\EventDispatcherTaskEvent`. Every `EventDispatcherTask` without `event_name` then
+  triggers the same listeners.
diff --git a/src/Task/Event/EventDispatcherTask.php b/src/Task/Event/EventDispatcherTask.php
index fcf8bc92..e33373f9 100644
--- a/src/Task/Event/EventDispatcherTask.php
+++ b/src/Task/Event/EventDispatcherTask.php
@@ -39,14 +39,14 @@ public function execute(ProcessState $state): void
 
         $event = new EventDispatcherTaskEvent($state);
 
-        $this->eventDispatcher->dispatch($event);
+        $this->eventDispatcher->dispatch($event, $options['event_name']);
     }
 
     protected function configureOptions(OptionsResolver $resolver): void
     {
-        $resolver->setRequired(['event_name']);
+        $resolver->setDefault('event_name', null);
         $resolver->setDefault('passive', true);
-        $resolver->setAllowedTypes('event_name', ['string']);
+        $resolver->setAllowedTypes('event_name', ['null', 'string']);
         $resolver->setAllowedTypes('passive', ['boolean']);
     }
 }