diff --git a/.travis.yml b/.travis.yml
index c9591bd..f6df0a2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ php:
     - '7.1'
     - '7.2'
     - '7.3'
+    - '7.4'
     - nightly
 
 env:
diff --git a/README.md b/README.md
index 9e101d6..f136ce2 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ We assume you have a minimum knowledge of how Push Notifications work, otherwise
 * You have an eCommerce app:
     * Notify your customer their order has been shipped
     * Notify your category manager they sell a product
-    
+
 
 ## Summary
 
@@ -43,7 +43,7 @@ This bundle is just the back-end part of the subscription process. For the front
 PHP7.1+ is required.
 
 ```bash
-composer require bentools/webpush-bundle 0.5.*
+composer require bentools/webpush-bundle 0.6.*
 ```
 
 If you're using Symfony 3, add the bundle to your kernel. With Symfony Flex, this should be done automatically.
diff --git a/composer.json b/composer.json
index bdbac33..ac4610d 100644
--- a/composer.json
+++ b/composer.json
@@ -16,22 +16,22 @@
     "ext-mbstring": "*",
     "ext-openssl": "*",
     "guzzlehttp/guzzle": "~6.0",
-    "minishlink/web-push": "^4.0|^5.0",
-    "symfony/http-kernel": "^3.0|^4.0"
+    "minishlink/web-push": "~4.0|~5.0",
+    "symfony/http-kernel": "~3.0|~4.0|~5.0"
   },
   "require-dev": {
     "bentools/doctrine-static": "1.0.x-dev",
     "doctrine/dbal": "~2.5",
-    "nyholm/symfony-bundle-test": "^1.4",
-    "phpunit/phpunit": "^5.0|^6.0|^7.0",
-    "symfony/config": "^4.0",
-    "symfony/dependency-injection": "^3.0|^4.0",
-    "symfony/framework-bundle": "^3.0|^4.0",
-    "symfony/http-foundation": "^3.0|^4.0",
-    "symfony/routing": "^3.0|^4.0",
-    "symfony/security": "^3.0|^4.0",
-    "symfony/var-dumper": "^3.0|^4.0",
-    "symfony/yaml": "^3.0|^4.0",
+    "nyholm/symfony-bundle-test": "~1.4",
+    "phpunit/phpunit": "~5.0|~6.0|~7.0",
+    "symfony/config": "~4.0",
+    "symfony/dependency-injection": "~3.0|~4.0|~5.0",
+    "symfony/framework-bundle": "~3.0|~4.0|~5.0",
+    "symfony/http-foundation": "~3.0|~4.0|~5.0",
+    "symfony/routing": "~3.0|~4.0|~5.0",
+    "symfony/security": "~3.0|~4.0|~5.0",
+    "symfony/var-dumper": "~3.0|~4.0|~5.0",
+    "symfony/yaml": "~3.0|~4.0|~5.0",
     "twig/twig": "~1.0|~2.0"
   },
   "autoload": {
diff --git a/src/Action/RegisterSubscriptionAction.php b/src/Action/RegisterSubscriptionAction.php
index f64b240..2e132f7 100644
--- a/src/Action/RegisterSubscriptionAction.php
+++ b/src/Action/RegisterSubscriptionAction.php
@@ -5,6 +5,7 @@
 use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionManagerRegistry;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
 use Symfony\Component\Security\Core\User\UserInterface;
@@ -18,7 +19,6 @@ final class RegisterSubscriptionAction
 
     /**
      * RegisterSubscriptionAction constructor.
-     * @param UserSubscriptionManagerRegistry $registry
      */
     public function __construct(UserSubscriptionManagerRegistry $registry)
     {
@@ -26,10 +26,6 @@ public function __construct(UserSubscriptionManagerRegistry $registry)
     }
 
     /**
-     * @param UserInterface $user
-     * @param string        $subscriptionHash
-     * @param array         $subscription
-     * @param array         $options
      * @throws \InvalidArgumentException
      * @throws \RuntimeException
      * @throws \Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException
@@ -44,8 +40,6 @@ private function subscribe(UserInterface $user, string $subscriptionHash, array
     }
 
     /**
-     * @param UserInterface $user
-     * @param string        $subscriptionHash
      * @throws BadRequestHttpException
      * @throws \RuntimeException
      */
@@ -54,18 +48,16 @@ private function unsubscribe(UserInterface $user, string $subscriptionHash)
         $manager = $this->registry->getManager($user);
         $subscription = $manager->getUserSubscription($user, $subscriptionHash);
         if (null === $subscription) {
-            throw new BadRequestHttpException("Subscription hash not found");
+            throw new BadRequestHttpException('Subscription hash not found');
         }
         $manager->delete($subscription);
     }
 
-    /**
-     * @param Request       $request
-     * @param UserInterface $user
-     * @return Response
-     */
-    public function __invoke(Request $request, UserInterface $user): Response
+    public function __invoke(Request $request, UserInterface $user = null): Response
     {
+        if (null === $user) {
+            throw new AccessDeniedHttpException('Not authenticated.');
+        }
 
         if (!in_array($request->getMethod(), ['POST', 'DELETE'])) {
             throw new MethodNotAllowedHttpException(['POST', 'DELETE']);
diff --git a/src/Command/WebPushGenerateKeysCommand.php b/src/Command/WebPushGenerateKeysCommand.php
index 433faaa..3a3ceeb 100644
--- a/src/Command/WebPushGenerateKeysCommand.php
+++ b/src/Command/WebPushGenerateKeysCommand.php
@@ -3,14 +3,16 @@
 namespace BenTools\WebPushBundle\Command;
 
 use Minishlink\WebPush\VAPID;
-use Symfony\Bundle\FrameworkBundle\Command\ContainerAwareCommand;
+use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
 use Symfony\Component\HttpKernel\Kernel;
 
-final class WebPushGenerateKeysCommand extends ContainerAwareCommand
+final class WebPushGenerateKeysCommand extends Command
 {
+    protected static $defaultName = 'webpush:generate:keys';
+
     /**
      * {@inheritdoc}
      */
@@ -24,7 +26,7 @@ protected function configure()
     /**
      * {@inheritdoc}
      */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $io = new SymfonyStyle($input, $output);
         $keys = VAPID::createVapidKeys();
@@ -50,5 +52,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         private_key: '{$keys['privateKey']}'    
 EOF
         );
+
+        return 0;
     }
 }
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 01802fd..65ad5c5 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -4,13 +4,19 @@
 
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
+use Symfony\Component\HttpKernel\Kernel;
 
 class Configuration implements ConfigurationInterface
 {
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('bentools_webpush');
+        if (Kernel::MAJOR_VERSION < 4) {
+            $treeBuilder = new TreeBuilder();
+            $rootNode = $treeBuilder->root('bentools_webpush');
+        } else {
+            $treeBuilder = new TreeBuilder('bentools_webpush');
+            $rootNode = $treeBuilder->getRootNode();
+        }
 
         $rootNode
             ->children()
diff --git a/src/DependencyInjection/WebPushCompilerPass.php b/src/DependencyInjection/WebPushCompilerPass.php
index 8bb1c88..f10264f 100644
--- a/src/DependencyInjection/WebPushCompilerPass.php
+++ b/src/DependencyInjection/WebPushCompilerPass.php
@@ -9,7 +9,6 @@
 
 final class WebPushCompilerPass implements CompilerPassInterface
 {
-
     public function process(ContainerBuilder $container)
     {
         $registry = $container->getDefinition(UserSubscriptionManagerRegistry::class);
diff --git a/src/DependencyInjection/WebPushExtension.php b/src/DependencyInjection/WebPushExtension.php
index 45f13af..aa8189d 100644
--- a/src/DependencyInjection/WebPushExtension.php
+++ b/src/DependencyInjection/WebPushExtension.php
@@ -10,7 +10,7 @@
 /**
  * This is the class that loads and manages your bundle configuration.
  *
- * @link http://symfony.com/doc/current/cookbook/bundles/extension.html
+ * @see http://symfony.com/doc/current/cookbook/bundles/extension.html
  */
 class WebPushExtension extends Extension
 {
@@ -25,12 +25,12 @@ public function load(array $configs, ContainerBuilder $container)
         $container->setParameter('bentools_webpush.vapid_subject', $config['settings']['subject'] ?? $container->getParameter('router.request_context.host'));
         $container->setParameter('bentools_webpush.vapid_public_key', $config['settings']['public_key'] ?? null);
         $container->setParameter('bentools_webpush.vapid_private_key', $config['settings']['private_key'] ?? null);
-        $loader = new XmlFileLoader($container, new FileLocator([__DIR__ . '/../Resources/config/']));
+        $loader = new XmlFileLoader($container, new FileLocator([__DIR__.'/../Resources/config/']));
         $loader->load('services.xml');
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function getAlias()
     {
diff --git a/src/Model/Message/PushMessage.php b/src/Model/Message/PushMessage.php
index bb61403..f6126ca 100644
--- a/src/Model/Message/PushMessage.php
+++ b/src/Model/Message/PushMessage.php
@@ -6,18 +6,16 @@
  * A message is an enveloppe that contain:
  * - An optional payload
  * - An optional array of options (like TTL, Topic, etc)
- * - An optional array of authentication data (if different from the client)
+ * - An optional array of authentication data (if different from the client).
  */
 final class PushMessage
 {
-
-    private $payload, $options, $auth;
+    private $payload;
+    private $options;
+    private $auth;
 
     /**
      * PushMessage constructor.
-     * @param null|string $payload
-     * @param array $options
-     * @param array $auth
      */
     public function __construct(?string $payload = null, array $options = [], array $auth = [])
     {
@@ -26,46 +24,34 @@ public function __construct(?string $payload = null, array $options = [], array
         $this->auth = $auth;
     }
 
-    /**
-     * @param null|string $payload
-     */
     public function setPayload(?string $payload): void
     {
         $this->payload = $payload;
     }
 
-    /**
-     * @return null|string
-     */
     public function getPayload(): ?string
     {
         return $this->payload;
     }
 
-    /**
-     * @param int $ttl
-     */
     public function setTTL(int $ttl): void
     {
         $this->options['TTL'] = $ttl;
     }
 
-    /**
-     * @param null|string $topic
-     */
     public function setTopic(?string $topic): void
     {
         $this->options['topic'] = $topic;
     }
 
     /**
-     * @param null|string $urgency
      * @throws \InvalidArgumentException
      */
     public function setUrgency(?string $urgency): void
     {
         if (null === $urgency) {
             unset($this->options['urgency']);
+
             return;
         }
 
@@ -76,9 +62,6 @@ public function setUrgency(?string $urgency): void
         $this->options['urgency'] = $urgency;
     }
 
-    /**
-     * @return array
-     */
     public function getOptions(): array
     {
         return array_diff($this->options, array_filter($this->options, 'is_null'));
@@ -89,9 +72,6 @@ public function getOption(string $key)
         return $this->options[$key] ?? null;
     }
 
-    /**
-     * @return array
-     */
     public function getAuth(): array
     {
         return $this->auth;
diff --git a/src/Model/Message/PushNotification.php b/src/Model/Message/PushNotification.php
index 06bf8a9..b87ab76 100644
--- a/src/Model/Message/PushNotification.php
+++ b/src/Model/Message/PushNotification.php
@@ -7,7 +7,6 @@
 
 final class PushNotification implements JsonSerializable, ArrayAccess
 {
-
     const BODY = 'body';
     const ICON = 'icon';
     const IMAGE = 'image';
@@ -24,7 +23,7 @@ final class PushNotification implements JsonSerializable, ArrayAccess
     const TIMESTAMP = 'timestamp';
 
     /**
-     * @var null|string
+     * @var string|null
      */
     private $title;
 
@@ -35,8 +34,6 @@ final class PushNotification implements JsonSerializable, ArrayAccess
 
     /**
      * PushNotification constructor.
-     * @param null|string $title
-     * @param array $options
      */
     public function __construct(?string $title, array $options = [])
     {
@@ -44,47 +41,34 @@ public function __construct(?string $title, array $options = [])
         $this->options = $options;
     }
 
-    /**
-     * @return null|string
-     */
     public function getTitle(): ?string
     {
         return $this->title;
     }
 
-
-    /**
-     * @param null|string $title
-     */
     public function setTitle(?string $title): void
     {
         $this->title = $title;
     }
 
-    /**
-     * @return array
-     */
     public function getOptions(): array
     {
         return $this->options;
     }
 
-    /**
-     * @param array $options
-     */
     public function setOptions(array $options): void
     {
         $this->options = $options;
     }
 
     /**
-     * @param string $key
      * @param mixed $value
      */
     public function setOption(string $key, $value): void
     {
         if (null === $value) {
             unset($this->options[$key]);
+
             return;
         }
 
@@ -96,45 +80,38 @@ public function getOption($key)
         return $this->options[$key] ?? null;
     }
 
-    /**
-     * @param array $options
-     * @param array $auth
-     * @return PushMessage
-     */
     public function createMessage(array $options = [], array $auth = []): PushMessage
     {
         return new PushMessage((string) $this, $options, $auth);
     }
 
-    /**
-     * @return array
-     */
     public function jsonSerialize(): array
     {
         return [
-            'title'   => $this->title,
+            'title' => $this->title,
             'options' => array_diff($this->options, array_filter($this->options, 'is_null')),
         ];
     }
 
-    /**
-     * @return string
-     */
     public function __toString(): string
     {
         return (string) json_encode($this);
     }
 
     /**
-     * Whether a offset exists
-     * @link https://php.net/manual/en/arrayaccess.offsetexists.php
+     * Whether a offset exists.
+     *
+     * @see https://php.net/manual/en/arrayaccess.offsetexists.php
+     *
      * @param mixed $offset <p>
-     * An offset to check for.
-     * </p>
-     * @return boolean true on success or false on failure.
-     * </p>
-     * <p>
-     * The return value will be casted to boolean if non-boolean was returned.
+     *                      An offset to check for.
+     *                      </p>
+     *
+     * @return bool true on success or false on failure.
+     *              </p>
+     *              <p>
+     *              The return value will be casted to boolean if non-boolean was returned.
+     *
      * @since 5.0.0
      */
     public function offsetExists($offset)
@@ -143,12 +120,16 @@ public function offsetExists($offset)
     }
 
     /**
-     * Offset to retrieve
-     * @link https://php.net/manual/en/arrayaccess.offsetget.php
+     * Offset to retrieve.
+     *
+     * @see https://php.net/manual/en/arrayaccess.offsetget.php
+     *
      * @param mixed $offset <p>
-     * The offset to retrieve.
-     * </p>
-     * @return mixed Can return all value types.
+     *                      The offset to retrieve.
+     *                      </p>
+     *
+     * @return mixed can return all value types
+     *
      * @since 5.0.0
      */
     public function offsetGet($offset)
@@ -157,15 +138,19 @@ public function offsetGet($offset)
     }
 
     /**
-     * Offset to set
-     * @link https://php.net/manual/en/arrayaccess.offsetset.php
+     * Offset to set.
+     *
+     * @see https://php.net/manual/en/arrayaccess.offsetset.php
+     *
      * @param mixed $offset <p>
-     * The offset to assign the value to.
-     * </p>
-     * @param mixed $value <p>
-     * The value to set.
-     * </p>
+     *                      The offset to assign the value to.
+     *                      </p>
+     * @param mixed $value  <p>
+     *                      The value to set.
+     *                      </p>
+     *
      * @return void
+     *
      * @since 5.0.0
      */
     public function offsetSet($offset, $value)
@@ -174,12 +159,16 @@ public function offsetSet($offset, $value)
     }
 
     /**
-     * Offset to unset
-     * @link https://php.net/manual/en/arrayaccess.offsetunset.php
+     * Offset to unset.
+     *
+     * @see https://php.net/manual/en/arrayaccess.offsetunset.php
+     *
      * @param mixed $offset <p>
-     * The offset to unset.
-     * </p>
+     *                      The offset to unset.
+     *                      </p>
+     *
      * @return void
+     *
      * @since 5.0.0
      */
     public function offsetUnset($offset)
diff --git a/src/Model/Response/PushResponse.php b/src/Model/Response/PushResponse.php
index 09dc499..a3aeb26 100644
--- a/src/Model/Response/PushResponse.php
+++ b/src/Model/Response/PushResponse.php
@@ -25,8 +25,6 @@ final class PushResponse
 
     /**
      * WebPushResponse constructor.
-     * @param UserSubscriptionInterface $subscription
-     * @param int                       $statusCode
      */
     public function __construct(UserSubscriptionInterface $subscription, int $statusCode)
     {
@@ -34,33 +32,21 @@ public function __construct(UserSubscriptionInterface $subscription, int $status
         $this->statusCode = $statusCode;
     }
 
-    /**
-     * @return UserSubscriptionInterface
-     */
     public function getSubscription(): UserSubscriptionInterface
     {
         return $this->subscription;
     }
 
-    /**
-     * @return int
-     */
     public function getStatusCode(): int
     {
         return $this->statusCode;
     }
 
-    /**
-     * @return bool
-     */
     public function isExpired(): bool
     {
         return in_array($this->statusCode, [self::NOT_FOUND, self::GONE]);
     }
 
-    /**
-     * @return bool
-     */
     public function isSuccessFul(): bool
     {
         return self::SUCCESS === $this->statusCode;
diff --git a/src/Model/Subscription/UserSubscriptionInterface.php b/src/Model/Subscription/UserSubscriptionInterface.php
index 92c449e..77ef6dd 100644
--- a/src/Model/Subscription/UserSubscriptionInterface.php
+++ b/src/Model/Subscription/UserSubscriptionInterface.php
@@ -6,46 +6,33 @@
 
 interface UserSubscriptionInterface
 {
-
     /**
      * Return the user associated to this subscription.
-     *
-     * @return UserInterface
      */
     public function getUser(): UserInterface;
 
     /**
      * Return the hash of this subscription. Can be a fingerprint or a cookie.
-     *
-     * @return string
      */
     public function getSubscriptionHash(): string;
 
     /**
      * Return the subscriber's HTTP endpoint.
-     *
-     * @return string
      */
     public function getEndpoint(): string;
 
     /**
      * Return the subscriber's public key.
-     *
-     * @return string
      */
     public function getPublicKey(): string;
 
     /**
      * Return the subscriber auth token.
-     *
-     * @return string
      */
     public function getAuthToken(): string;
 
     /**
      * Content-encoding (default: aesgcm).
-     *
-     * @return string
      */
     public function getContentEncoding(): string;
 }
diff --git a/src/Model/Subscription/UserSubscriptionManagerInterface.php b/src/Model/Subscription/UserSubscriptionManagerInterface.php
index 66a6156..307e457 100644
--- a/src/Model/Subscription/UserSubscriptionManagerInterface.php
+++ b/src/Model/Subscription/UserSubscriptionManagerInterface.php
@@ -6,42 +6,26 @@
 
 interface UserSubscriptionManagerInterface
 {
-
     /**
      * Create a user/subscription association.
-     *
-     * @param UserInterface $user
-     * @param string        $subscriptionHash
-     * @param array         $subscription
-     * @param array         $options
-     * @return UserSubscriptionInterface
      */
     public function factory(UserInterface $user, string $subscriptionHash, array $subscription, array $options = []): UserSubscriptionInterface;
 
     /**
      * Return a string representation of the subscription's endpoint.
      * Example: md5($endpoint).
-     *
-     * @param string             $endpoint
-     * @param UserInterface $user
-     * @return string
      */
     public function hash(string $endpoint, UserInterface $user): string;
 
     /**
      * Return the subscription attached to this user.
-     *
-     * @param UserInterface $user
-     * @param string        $subscriptionHash
-     * @return UserSubscriptionInterface|null
      */
     public function getUserSubscription(UserInterface $user, string $subscriptionHash): ?UserSubscriptionInterface;
 
     /**
      * Return the list of known subscriptions for this user.
-     * A user can have several subscriptions (on chrome, firefox, etc.)
+     * A user can have several subscriptions (on chrome, firefox, etc.).
      *
-     * @param UserInterface $user
      * @return iterable|UserSubscriptionInterface[]
      */
     public function findByUser(UserInterface $user): iterable;
@@ -49,23 +33,16 @@ public function findByUser(UserInterface $user): iterable;
     /**
      * Return the list of known subscriptions for this hash.
      * Several users can share the same hash.
-     *
-     * @param string $subscriptionHash
-     * @return iterable
      */
     public function findByHash(string $subscriptionHash): iterable;
 
     /**
      * Store the user/subscription association.
-     *
-     * @param UserSubscriptionInterface $userSubscription
      */
     public function save(UserSubscriptionInterface $userSubscription): void;
 
     /**
      * Remove the user/subscription association.
-     *
-     * @param UserSubscriptionInterface $userSubscription
      */
     public function delete(UserSubscriptionInterface $userSubscription): void;
 }
diff --git a/src/Model/Subscription/UserSubscriptionManagerRegistry.php b/src/Model/Subscription/UserSubscriptionManagerRegistry.php
index d4f174e..b507c9f 100644
--- a/src/Model/Subscription/UserSubscriptionManagerRegistry.php
+++ b/src/Model/Subscription/UserSubscriptionManagerRegistry.php
@@ -15,8 +15,6 @@ final class UserSubscriptionManagerRegistry implements UserSubscriptionManagerIn
     private $registry = [];
 
     /**
-     * @param string                           $userClass
-     * @param UserSubscriptionManagerInterface $userSubscriptionManager
      * @throws \InvalidArgumentException
      */
     public function register(string $userClass, UserSubscriptionManagerInterface $userSubscriptionManager)
@@ -38,7 +36,7 @@ public function register(string $userClass, UserSubscriptionManagerInterface $us
 
     /**
      * @param UserInterface|string $userClass
-     * @return UserSubscriptionManagerInterface
+     *
      * @throws RuntimeException
      * @throws ServiceNotFoundException
      * @throws \InvalidArgumentException
@@ -47,13 +45,7 @@ public function register(string $userClass, UserSubscriptionManagerInterface $us
     public function getManager($userClass): UserSubscriptionManagerInterface
     {
         if (!is_a($userClass, UserInterface::class, true)) {
-            throw new \InvalidArgumentException(
-                sprintf(
-                    'Expected class or object that implements %s, %s given',
-                    UserInterface::class,
-                    is_object($userClass) ? get_class($userClass) : gettype($userClass)
-                )
-            );
+            throw new \InvalidArgumentException(sprintf('Expected class or object that implements %s, %s given', UserInterface::class, is_object($userClass) ? get_class($userClass) : gettype($userClass)));
         }
 
         if (is_object($userClass)) {
@@ -73,7 +65,7 @@ public function getManager($userClass): UserSubscriptionManagerInterface
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function factory(UserInterface $user, string $subscriptionHash, array $subscription, array $options = []): UserSubscriptionInterface
     {
@@ -81,7 +73,7 @@ public function factory(UserInterface $user, string $subscriptionHash, array $su
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function hash(string $endpoint, UserInterface $user): string
     {
@@ -89,7 +81,7 @@ public function hash(string $endpoint, UserInterface $user): string
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function getUserSubscription(UserInterface $user, string $subscriptionHash): ?UserSubscriptionInterface
     {
@@ -97,7 +89,7 @@ public function getUserSubscription(UserInterface $user, string $subscriptionHas
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function findByUser(UserInterface $user): iterable
     {
@@ -105,7 +97,7 @@ public function findByUser(UserInterface $user): iterable
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function findByHash(string $subscriptionHash): iterable
     {
@@ -117,7 +109,7 @@ public function findByHash(string $subscriptionHash): iterable
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function save(UserSubscriptionInterface $userSubscription): void
     {
@@ -125,7 +117,7 @@ public function save(UserSubscriptionInterface $userSubscription): void
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function delete(UserSubscriptionInterface $userSubscription): void
     {
diff --git a/src/Sender/NullPushMessageSender.php b/src/Sender/NullPushMessageSender.php
index 2e04418..5d17afe 100644
--- a/src/Sender/NullPushMessageSender.php
+++ b/src/Sender/NullPushMessageSender.php
@@ -9,7 +9,7 @@ final class NullPushMessageSender implements PushMessagerSenderInterface
     /**
      * Does nothing.
      *
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function push(PushMessage $message, iterable $subscriptions): iterable
     {
diff --git a/src/Sender/PushMessageSender.php b/src/Sender/PushMessageSender.php
index 7c0e66d..c98478b 100644
--- a/src/Sender/PushMessageSender.php
+++ b/src/Sender/PushMessageSender.php
@@ -3,8 +3,8 @@
 namespace BenTools\WebPushBundle\Sender;
 
 use BenTools\WebPushBundle\Model\Message\PushMessage;
-use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionInterface;
 use BenTools\WebPushBundle\Model\Response\PushResponse;
+use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionInterface;
 use GuzzleHttp\Client;
 use GuzzleHttp\ClientInterface;
 use GuzzleHttp\Exception\RequestException;
@@ -42,16 +42,12 @@ class PushMessageSender implements PushMessagerSenderInterface
 
     /**
      * PushMessageSender constructor.
-     * @param array $auth
-     * @param array $defaultOptions
-     * @param ClientInterface|null $client
      */
     public function __construct(
         array $auth = [],
         array $defaultOptions = [],
         ClientInterface $client = null
     ) {
-
         if (isset($auth['VAPID'])) {
             $auth['VAPID']['validated'] = false;
         }
@@ -62,9 +58,8 @@ public function __construct(
     }
 
     /**
-     * @param PushMessage $message
-     * @param iterable    $subscriptions
      * @return PushResponse[]
+     *
      * @throws \ErrorException
      * @throws \InvalidArgumentException
      * @throws \LogicException
@@ -100,7 +95,6 @@ public function push(PushMessage $message, iterable $subscriptions): iterable
                     return new PushResponse($subscription, $response->getStatusCode());
                 })
                 ->otherwise(function (\Throwable $reason) use ($subscription) {
-
                     if ($reason instanceof RequestException && $reason->hasResponse()) {
                         return new PushResponse($subscription, $reason->getResponse()->getStatusCode());
                     }
@@ -121,12 +115,9 @@ public function push(PushMessage $message, iterable $subscriptions): iterable
         return $promise->wait();
     }
 
-    /**
-     * @return bool
-     */
     public function isAutomaticPadding(): bool
     {
-        return $this->maxPaddingLength !== 0;
+        return 0 !== $this->maxPaddingLength;
     }
 
     /**
@@ -140,8 +131,6 @@ public function getMaxPaddingLength()
     /**
      * @param int|bool $maxPaddingLength Max padding length
      *
-     * @return self
-     *
      * @throws \Exception
      */
     public function setMaxPaddingLength($maxPaddingLength): self
@@ -150,9 +139,9 @@ public function setMaxPaddingLength($maxPaddingLength): self
             throw new \Exception('Automatic padding is too large. Max is '.Encryption::MAX_PAYLOAD_LENGTH.'. Recommended max is '.Encryption::MAX_COMPATIBILITY_PAYLOAD_LENGTH.' for compatibility reasons (see README).');
         } elseif ($maxPaddingLength < 0) {
             throw new \Exception('Padding length should be positive or zero.');
-        } elseif ($maxPaddingLength === true) {
+        } elseif (true === $maxPaddingLength) {
             $this->maxPaddingLength = Encryption::MAX_COMPATIBILITY_PAYLOAD_LENGTH;
-        } elseif ($maxPaddingLength === false) {
+        } elseif (false === $maxPaddingLength) {
             $this->maxPaddingLength = 0;
         } else {
             $this->maxPaddingLength = $maxPaddingLength;
@@ -161,9 +150,6 @@ public function setMaxPaddingLength($maxPaddingLength): self
         return $this;
     }
 
-    /**
-     * @return array
-     */
     public function getDefaultOptions(): array
     {
         return $this->defaultOptions;
diff --git a/src/Sender/PushMessagerSenderInterface.php b/src/Sender/PushMessagerSenderInterface.php
index e3d268c..de3adc6 100644
--- a/src/Sender/PushMessagerSenderInterface.php
+++ b/src/Sender/PushMessagerSenderInterface.php
@@ -3,8 +3,8 @@
 namespace BenTools\WebPushBundle\Sender;
 
 use BenTools\WebPushBundle\Model\Message\PushMessage;
-use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionInterface;
 use BenTools\WebPushBundle\Model\Response\PushResponse;
+use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionInterface;
 
 interface PushMessagerSenderInterface
 {
@@ -12,8 +12,8 @@ interface PushMessagerSenderInterface
      * Push a notification.
      * The implementation MUST adapt the payload with proper padding, etc.
      *
-     * @param PushMessage                 $message
      * @param UserSubscriptionInterface[] $subscriptions
+     *
      * @return PushResponse[]
      */
     public function push(PushMessage $message, iterable $subscriptions): iterable;
diff --git a/src/Sender/RequestBuilder.php b/src/Sender/RequestBuilder.php
index cedfb73..3ff45ae 100644
--- a/src/Sender/RequestBuilder.php
+++ b/src/Sender/RequestBuilder.php
@@ -6,23 +6,20 @@
 use BenTools\WebPushBundle\Model\Message\PushMessage;
 use BenTools\WebPushBundle\Model\Subscription\UserSubscriptionInterface;
 use GuzzleHttp\Psr7\Request;
+use function GuzzleHttp\Psr7\stream_for;
 use GuzzleHttp\Psr7\Uri;
 use Minishlink\WebPush\Encryption;
 use Minishlink\WebPush\Utils;
 use Minishlink\WebPush\VAPID;
 use Psr\Http\Message\RequestInterface;
-use function GuzzleHttp\Psr7\stream_for;
 
 final class RequestBuilder
 {
     private const FCM_BASE_URL = 'https://fcm.googleapis.com';
 
     /**
-     * @param PushMessage               $message
-     * @param UserSubscriptionInterface $subscription
-     * @param int                       $ttl
-     * @param int                       $maxPaddingLength
-     * @return RequestInterface
+     * @param int $maxPaddingLength
+     *
      * @throws \ErrorException
      * @throws \InvalidArgumentException
      */
@@ -36,13 +33,11 @@ public function createRequest(
         $request = $this->withOptionalHeaders($request, $message);
         $request = $request->withHeader('TTL', $ttl);
 
-
         if (null !== $message->getPayload() && null !== $subscription->getPublicKey() && null !== $subscription->getAuthToken()) {
             $request = $request
                 ->withHeader('Content-Type', 'application/octet-stream')
                 ->withHeader('Content-Encoding', $subscription->getContentEncoding());
 
-
             $payload = $this->getNormalizedPayload($message->getPayload(), $subscription->getContentEncoding(), $maxPaddingLength);
 
             $encrypted = Encryption::encrypt(
@@ -53,39 +48,33 @@ public function createRequest(
             );
 
             if ('aesgcm' === $subscription->getContentEncoding()) {
-                $request = $request->withHeader('Encryption', 'salt=' . Base64Url::encode($encrypted['salt']))
-                    ->withHeader('Crypto-Key', 'dh=' . Base64Url::encode($encrypted['localPublicKey']));
+                $request = $request->withHeader('Encryption', 'salt='.Base64Url::encode($encrypted['salt']))
+                    ->withHeader('Crypto-Key', 'dh='.Base64Url::encode($encrypted['localPublicKey']));
             }
 
             $encryptionContentCodingHeader = Encryption::getContentCodingHeader($encrypted['salt'], $encrypted['localPublicKey'], $subscription->getContentEncoding());
-            $content = $encryptionContentCodingHeader . $encrypted['cipherText'];
+            $content = $encryptionContentCodingHeader.$encrypted['cipherText'];
 
             return $request
                 ->withBody(stream_for($content))
                 ->withHeader('Content-Length', Utils::safeStrlen($content));
         }
 
-
         return $request
             ->withHeader('Content-Length', 0);
     }
 
     /**
-     * @param RequestInterface          $request
-     * @param array                     $vapid
-     * @param UserSubscriptionInterface $subscription
-     * @return RequestInterface
      * @throws \ErrorException
      * @throws \InvalidArgumentException
      */
     public function withVAPIDAuthentication(RequestInterface $request, array $vapid, UserSubscriptionInterface $subscription): RequestInterface
     {
-
         $endpoint = $subscription->getEndpoint();
-        $audience = parse_url($endpoint, PHP_URL_SCHEME) . '://' . parse_url($endpoint, PHP_URL_HOST);
+        $audience = parse_url($endpoint, PHP_URL_SCHEME).'://'.parse_url($endpoint, PHP_URL_HOST);
 
         if (!parse_url($audience)) {
-            throw new \ErrorException('Audience "' . $audience . '"" could not be generated.');
+            throw new \ErrorException('Audience "'.$audience.'"" could not be generated.');
         }
 
         $vapidHeaders = VAPID::getVapidHeaders($audience, $vapid['subject'], $vapid['publicKey'], $vapid['privateKey'], $subscription->getContentEncoding());
@@ -94,12 +83,12 @@ public function withVAPIDAuthentication(RequestInterface $request, array $vapid,
 
         if ('aesgcm' === $subscription->getContentEncoding()) {
             if ($request->hasHeader('Crypto-Key')) {
-                $request = $request->withHeader('Crypto-Key', $request->getHeaderLine('Crypto-Key') . ';' . $vapidHeaders['Crypto-Key']);
+                $request = $request->withHeader('Crypto-Key', $request->getHeaderLine('Crypto-Key').';'.$vapidHeaders['Crypto-Key']);
             } else {
                 $headers['Crypto-Key'] = $vapidHeaders['Crypto-Key'];
                 $request->withHeader('Crypto-Key', $vapidHeaders['Crypto-Key']);
             }
-        } else if ('aes128gcm' === $subscription->getContentEncoding() && substr($endpoint, 0, strlen(self::FCM_BASE_URL)) === self::FCM_BASE_URL) {
+        } elseif ('aes128gcm' === $subscription->getContentEncoding() && self::FCM_BASE_URL === substr($endpoint, 0, strlen(self::FCM_BASE_URL))) {
             $request = $request->withUri(new Uri(str_replace('fcm/send', 'wp', $endpoint)));
         }
 
@@ -107,20 +96,14 @@ public function withVAPIDAuthentication(RequestInterface $request, array $vapid,
     }
 
     /**
-     * @param RequestInterface $request
-     * @param string           $apiKey
-     * @return RequestInterface
      * @throws \InvalidArgumentException
      */
     public function withGCMAuthentication(RequestInterface $request, string $apiKey): RequestInterface
     {
-        return $request->withHeader('Authorization', 'key=' . $apiKey);
+        return $request->withHeader('Authorization', 'key='.$apiKey);
     }
 
     /**
-     * @param RequestInterface $request
-     * @param PushMessage      $message
-     * @return RequestInterface
      * @throws \InvalidArgumentException
      */
     private function withOptionalHeaders(RequestInterface $request, PushMessage $message): RequestInterface
@@ -135,10 +118,8 @@ private function withOptionalHeaders(RequestInterface $request, PushMessage $mes
     }
 
     /**
-     * @param null|string $payload
-     * @param string      $contentEncoding
-     * @param mixed       $automaticPadding
-     * @return null|string
+     * @param mixed $automaticPadding
+     *
      * @throws \ErrorException
      */
     private function getNormalizedPayload(?string $payload, string $contentEncoding, $automaticPadding): ?string
@@ -147,7 +128,7 @@ private function getNormalizedPayload(?string $payload, string $contentEncoding,
             return null;
         }
         if (Utils::safeStrlen($payload) > Encryption::MAX_PAYLOAD_LENGTH) {
-            throw new \ErrorException('Size of payload must not be greater than ' . Encryption::MAX_PAYLOAD_LENGTH . ' bytes.');
+            throw new \ErrorException('Size of payload must not be greater than '.Encryption::MAX_PAYLOAD_LENGTH.' bytes.');
         }
 
         return Encryption::padPayload($payload, $automaticPadding, $contentEncoding);
diff --git a/src/Twig/WebPushTwigExtension.php b/src/Twig/WebPushTwigExtension.php
index 019d294..65957ab 100644
--- a/src/Twig/WebPushTwigExtension.php
+++ b/src/Twig/WebPushTwigExtension.php
@@ -18,9 +18,9 @@ public function __construct(?string $publicKey)
     }
 
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
-    public function getGlobals()
+    public function getGlobals(): array
     {
         return [
             'bentools_webpush' => [
diff --git a/src/WebPushBundle.php b/src/WebPushBundle.php
index efc59df..70147e6 100644
--- a/src/WebPushBundle.php
+++ b/src/WebPushBundle.php
@@ -10,7 +10,7 @@
 class WebPushBundle extends Bundle
 {
     /**
-     * @inheritDoc
+     * {@inheritdoc}
      */
     public function getContainerExtension()
     {