diff --git a/.travis.yml b/.travis.yml
index 57310fda..1e22edf4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,7 +23,7 @@ matrix:
         - php: 7.2
           env: SYMFONY_VERSION="~4.2.0" WITH_LIIP_IMAGINE=true
         - php: 7.3
-          env: SYMFONY_VERSION="~4.2.0" WITH_LIIP_IMAGINE=true
+          env: SYMFONY_VERSION="~4.3.0" WITH_LIIP_IMAGINE=true
     allow_failures:
         - php: nightly
 
diff --git a/Event/Event.php b/Event/Event.php
index bb5e3254..4eb937d5 100644
--- a/Event/Event.php
+++ b/Event/Event.php
@@ -3,42 +3,79 @@
 namespace Vich\UploaderBundle\Event;
 
 use Symfony\Component\EventDispatcher\Event as BaseEvent;
+use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Contracts\EventDispatcher\Event as ContractEvent;
 use Vich\UploaderBundle\Mapping\PropertyMapping;
 
-/**
+/*
  * Base class for upload events.
  *
  * @author Kévin Gomez <contact@kevingomez.fr>
  */
-class Event extends BaseEvent
-{
-    protected $object;
+if ('42' !== Kernel::MAJOR_VERSION.Kernel::MINOR_VERSION && class_exists(ContractEvent::class)) {
+    class Event extends ContractEvent
+    {
+        protected $object;
 
-    protected $mapping;
+        protected $mapping;
 
-    public function __construct($object, PropertyMapping $mapping)
-    {
-        $this->object = $object;
-        $this->mapping = $mapping;
-    }
+        public function __construct($object, PropertyMapping $mapping)
+        {
+            $this->object = $object;
+            $this->mapping = $mapping;
+        }
 
-    /**
-     * Accessor to the object being manipulated.
-     *
-     * @return object
-     */
-    public function getObject()
-    {
-        return $this->object;
-    }
+        /**
+         * Accessor to the object being manipulated.
+         *
+         * @return object
+         */
+        public function getObject()
+        {
+            return $this->object;
+        }
 
-    /**
-     * Accessor to the mapping used to manipulate the object.
-     *
-     * @return PropertyMapping
-     */
-    public function getMapping(): PropertyMapping
+        /**
+         * Accessor to the mapping used to manipulate the object.
+         *
+         * @return PropertyMapping
+         */
+        public function getMapping(): PropertyMapping
+        {
+            return $this->mapping;
+        }
+    }
+} else {
+    class Event extends BaseEvent
     {
-        return $this->mapping;
+        protected $object;
+
+        protected $mapping;
+
+        public function __construct($object, PropertyMapping $mapping)
+        {
+            $this->object = $object;
+            $this->mapping = $mapping;
+        }
+
+        /**
+         * Accessor to the object being manipulated.
+         *
+         * @return object
+         */
+        public function getObject()
+        {
+            return $this->object;
+        }
+
+        /**
+         * Accessor to the mapping used to manipulate the object.
+         *
+         * @return PropertyMapping
+         */
+        public function getMapping(): PropertyMapping
+        {
+            return $this->mapping;
+        }
     }
 }
diff --git a/Handler/UploadHandler.php b/Handler/UploadHandler.php
index 9b51b445..c56e6430 100644
--- a/Handler/UploadHandler.php
+++ b/Handler/UploadHandler.php
@@ -3,6 +3,8 @@
 namespace Vich\UploaderBundle\Handler;
 
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Contracts\EventDispatcher\Event as ContractEvent;
 use Symfony\Component\HttpFoundation\File\UploadedFile;
 use Vich\UploaderBundle\Event\Event;
 use Vich\UploaderBundle\Event\Events;
@@ -104,7 +106,11 @@ public function remove($obj, string $fieldName): void
 
     protected function dispatch(string $eventName, Event $event): void
     {
-        $this->dispatcher->dispatch($eventName, $event);
+        if ('42' !== Kernel::MAJOR_VERSION.Kernel::MINOR_VERSION && class_exists(ContractEvent::class)) {
+            $this->dispatcher->dispatch($event, $eventName);
+        } else {
+            $this->dispatcher->dispatch($eventName, $event);
+        }
     }
 
     protected function hasUploadedFile($obj, PropertyMapping $mapping): bool
diff --git a/Tests/Handler/UploadHandlerTest.php b/Tests/Handler/UploadHandlerTest.php
index 3d81c88c..5f2e5d97 100644
--- a/Tests/Handler/UploadHandlerTest.php
+++ b/Tests/Handler/UploadHandlerTest.php
@@ -3,9 +3,12 @@
 namespace Vich\UploaderBundle\Tests\Handler;
 
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Contracts\EventDispatcher\Event as ContractEvent;
 use Vich\TestBundle\Entity\Article;
 use Vich\UploaderBundle\Event\Event;
 use Vich\UploaderBundle\Event\Events;
+use Vich\UploaderBundle\Exception\MappingNotFoundException;
 use Vich\UploaderBundle\Handler\UploadHandler;
 use Vich\UploaderBundle\Injector\FileInjectorInterface;
 use Vich\UploaderBundle\Storage\StorageInterface;
@@ -14,7 +17,7 @@
 /**
  * @author Kévin Gomez <contact@kevingomez.fr>
  */
-class UploadHandlerTest extends TestCase
+final class UploadHandlerTest extends TestCase
 {
     protected $factory;
 
@@ -80,12 +83,12 @@ public function testUpload(): void
      */
     public function testAnExceptionIsThrownIfMappingIsntFound($method): void
     {
-        $this->expectException(\Vich\UploaderBundle\Exception\MappingNotFoundException::class);
+        $this->expectException(MappingNotFoundException::class);
 
         $this->factory = $this->getPropertyMappingFactoryMock();
         $handler = new UploadHandler($this->factory, $this->storage, $this->injector, $this->dispatcher);
 
-        \call_user_func([$handler, $method], $this->object, self::FILE_FIELD);
+        $handler->$method($this->object, self::FILE_FIELD);
     }
 
     public function methodProvider(): array
@@ -228,7 +231,7 @@ protected function validEvent()
         $object = $this->object;
         $mapping = $this->mapping;
 
-        return $this->callback(function ($event) use ($object, $mapping) {
+        return $this->callback(static function ($event) use ($object, $mapping) {
             return $event instanceof Event && $event->getObject() === $object && $event->getMapping() === $mapping;
         });
     }
@@ -236,10 +239,19 @@ protected function validEvent()
     protected function expectEvents(array $events): void
     {
         foreach ($events as $i => $event) {
-            $this->dispatcher
-                ->expects($this->at($i))
-                ->method('dispatch')
-                ->with($event, $this->validEvent());
+            if ('42' !== Kernel::MAJOR_VERSION.Kernel::MINOR_VERSION && class_exists(ContractEvent::class)) {
+                $this->dispatcher
+                    ->expects($this->at($i))
+                    ->method('dispatch')
+                    ->with($this->validEvent(), $event)
+                ;
+            } else {
+                $this->dispatcher
+                    ->expects($this->at($i))
+                    ->method('dispatch')
+                    ->with($event, $this->validEvent())
+                ;
+            }
         }
     }
 }
diff --git a/composer.json b/composer.json
index e94cc8d6..b59996e4 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
         "symfony/config": "^3.4 || ^4.0",
         "symfony/dependency-injection": "^3.4 || ^4.0",
         "symfony/event-dispatcher": "^3.4 || ^4.0",
-        "symfony/form": "^3.4 || ^4.0",
+        "symfony/form": "^3.4.19 || ^4.0",
         "symfony/http-foundation": "^3.4 || ^4.0",
         "symfony/http-kernel": "^3.4 || ^4.0",
         "symfony/property-access": "^3.4 || ^4.0",
@@ -38,13 +38,13 @@
         "matthiasnoback/symfony-dependency-injection-test": "^4.0",
         "mikey179/vfsstream": "^1.6",
         "oneup/flysystem-bundle": "^3.0",
-        "phpunit/phpunit": "^7.0 || ^8.0",
+        "phpunit/phpunit": "^8.0",
         "symfony/browser-kit": "^3.4 || ^4.0",
         "symfony/css-selector": "^3.4 || ^4.0",
         "symfony/doctrine-bridge": "^3.4 || ^4.0",
         "symfony/dom-crawler": "^3.4 || ^4.0",
-        "symfony/framework-bundle": "^3.4 || ^4.0",
-        "symfony/phpunit-bridge": "^3.3",
+        "symfony/framework-bundle": "^3.4.23 || ^4.2.4",
+        "symfony/phpunit-bridge": "^4.3",
         "symfony/security-csrf": "^3.4 || ^4.0",
         "symfony/translation": "^3.4 || ^4.0",
         "symfony/twig-bridge": "^3.4 || ^4.0",