diff -u b/src/EventSubscriber/DefaultSubscriber.php b/src/EventSubscriber/DefaultSubscriber.php
--- b/src/EventSubscriber/DefaultSubscriber.php
+++ b/src/EventSubscriber/DefaultSubscriber.php
@@ -3,6 +3,7 @@
 namespace Drupal\elasticsearch_connector_autocomp\EventSubscriber;
 
 use Drupal\Component\Utility\NestedArray;
+Symfony\Contracts\EventDispatcher\Event;
 use Drupal\Core\Database\Connection;
 use Drupal\elasticsearch_connector\ElasticSearch\Parameters\Factory\IndexFactory;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
@@ -54,7 +55,7 @@
   /**
    * Called on elasticsearch_connector.prepare_index_mapping event.
    *
-   * @param \Symfony\Component\EventDispatcher\Event $event
+   * @param \Symfony\Contracts\EventDispatcher\Event $event
    *   The event.
    */
   public function elasticsearchConnectorPrepareIndexMapping(Event $event) {
@@ -85,7 +86,7 @@
   /**
    * Called on elasticsearch_connector.prepare_index event.
    *
-   * @param \Symfony\Component\EventDispatcher\Event $event
+   * @param \Symfony\Contracts\EventDispatcher\Event $event
    *   The event.
    */
   public function elasticsearchConnectorPrepareIndex(Event $event) {