diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 33fd308..0ad379c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         operating-system: ['ubuntu-latest']
-        php-versions: ['7.1', '7.2', '7.3', '7.4', '8.0', '8.1']
+        php-versions: ['8.1', '8.2']
 
     steps:
       - name: Checkout
@@ -24,16 +24,7 @@ jobs:
           php-version: ${{ matrix.php-versions }}
           ini-values: post_max_size=256M, max_execution_time=180
 
-      # Legacy PHP versions ^7.1
       - name: Install Dependencies
-        if: ${{ matrix.php-versions < '8.0' }}
-        run: composer update $COMPOSER_FLAGS --no-interaction --prefer-dist --no-progress --ansi
-        env:
-          COMPOSER_FLAGS: "--prefer-lowest --prefer-stable"
-
-      # Modern PHP versions >= 8.0
-      - name: Install Dependencies
-        if: ${{ matrix.php-versions >= '8.0' }}
         run: composer update $COMPOSER_FLAGS --no-interaction --prefer-dist --no-progress --ansi
 
       - name: Process the tests
diff --git a/composer.json b/composer.json
index 697c602..0741c8a 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
         }
     ],
     "require": {
-        "php": ">=7.1",
+        "php": ">=8.1",
         "ext-curl": "*",
         "ext-json": "*",
         "ext-mbstring": "*",
diff --git a/src/Action/RegisterSubscriptionAction.php b/src/Action/RegisterSubscriptionAction.php
index 2e132f7..100584c 100644
--- a/src/Action/RegisterSubscriptionAction.php
+++ b/src/Action/RegisterSubscriptionAction.php
@@ -12,17 +12,11 @@
 
 final class RegisterSubscriptionAction
 {
-    /**
-     * @var UserSubscriptionManagerRegistry
-     */
-    private $registry;
-
     /**
      * RegisterSubscriptionAction constructor.
      */
-    public function __construct(UserSubscriptionManagerRegistry $registry)
+    public function __construct(private readonly UserSubscriptionManagerRegistry $registry)
     {
-        $this->registry = $registry;
     }
 
     /**
@@ -31,7 +25,7 @@ public function __construct(UserSubscriptionManagerRegistry $registry)
      * @throws \Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException
      * @throws \Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException
      */
-    private function subscribe(UserInterface $user, string $subscriptionHash, array $subscription, array $options = [])
+    private function subscribe(UserInterface $user, string $subscriptionHash, array $subscription, array $options = []): void
     {
         $manager = $this->registry->getManager($user);
         $userSubscription = $manager->getUserSubscription($user, $subscriptionHash)
@@ -43,7 +37,7 @@ private function subscribe(UserInterface $user, string $subscriptionHash, array
      * @throws BadRequestHttpException
      * @throws \RuntimeException
      */
-    private function unsubscribe(UserInterface $user, string $subscriptionHash)
+    private function unsubscribe(UserInterface $user, string $subscriptionHash): void
     {
         $manager = $this->registry->getManager($user);
         $subscription = $manager->getUserSubscription($user, $subscriptionHash);
diff --git a/src/Command/WebPushGenerateKeysCommand.php b/src/Command/WebPushGenerateKeysCommand.php
index 3a3ceeb..aea5ac1 100644
--- a/src/Command/WebPushGenerateKeysCommand.php
+++ b/src/Command/WebPushGenerateKeysCommand.php
@@ -25,6 +25,7 @@ protected function configure()
 
     /**
      * {@inheritdoc}
+     * @throws \ErrorException
      */
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
diff --git a/src/DependencyInjection/WebPushCompilerPass.php b/src/DependencyInjection/WebPushCompilerPass.php
index f10264f..aa3a1fb 100644
--- a/src/DependencyInjection/WebPushCompilerPass.php
+++ b/src/DependencyInjection/WebPushCompilerPass.php
@@ -9,7 +9,7 @@
 
 final class WebPushCompilerPass implements CompilerPassInterface
 {
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $registry = $container->getDefinition(UserSubscriptionManagerRegistry::class);
         $taggedSubscriptionManagers = $container->findTaggedServiceIds('bentools_webpush.subscription_manager');
diff --git a/src/DependencyInjection/WebPushExtension.php b/src/DependencyInjection/WebPushExtension.php
index bf2122a..7d6c651 100644
--- a/src/DependencyInjection/WebPushExtension.php
+++ b/src/DependencyInjection/WebPushExtension.php
@@ -17,7 +17,7 @@ class WebPushExtension extends Extension
     /**
      * {@inheritdoc}
      */
-    public function load(array $configs, ContainerBuilder $container)
+    public function load(array $configs, ContainerBuilder $container): void
     {
         $configuration = new Configuration();
 
diff --git a/src/Model/Message/PushMessage.php b/src/Model/Message/PushMessage.php
index f6126ca..2303b2d 100644
--- a/src/Model/Message/PushMessage.php
+++ b/src/Model/Message/PushMessage.php
@@ -10,19 +10,14 @@
  */
 final class PushMessage
 {
-    private $payload;
-    private $options;
-    private $auth;
-
     /**
      * PushMessage constructor.
      */
-    public function __construct(?string $payload = null, array $options = [], array $auth = [])
-    {
-        $this->payload = $payload;
-        $this->options = $options;
-        $this->auth = $auth;
-    }
+    public function __construct(
+        private ?string $payload = null,
+        private array $options   = [],
+        private array $auth      = [],
+    ) {}
 
     public function setPayload(?string $payload): void
     {
diff --git a/src/Model/Message/PushNotification.php b/src/Model/Message/PushNotification.php
index 1f91723..1e9b083 100644
--- a/src/Model/Message/PushNotification.php
+++ b/src/Model/Message/PushNotification.php
@@ -24,24 +24,13 @@ final class PushNotification implements JsonSerializable, ArrayAccess
     const ACTIONS = 'actions';
     const TIMESTAMP = 'timestamp';
 
-    /**
-     * @var string|null
-     */
-    private $title;
-
-    /**
-     * @var array
-     */
-    private $options;
-
     /**
      * PushNotification constructor.
      */
-    public function __construct(?string $title, array $options = [])
-    {
-        $this->title = $title;
-        $this->options = $options;
-    }
+    public function __construct(
+        private ?string $title,
+         private array $options = [],
+    ) {}
 
     public function getTitle(): ?string
     {
@@ -63,10 +52,7 @@ public function setOptions(array $options): void
         $this->options = $options;
     }
 
-    /**
-     * @param mixed $value
-     */
-    public function setOption(string $key, $value): void
+    public function setOption(string $key, mixed $value): void
     {
         if (null === $value) {
             unset($this->options[$key]);
@@ -77,7 +63,7 @@ public function setOption(string $key, $value): void
         $this->options[$key] = $value;
     }
 
-    public function getOption($key)
+    public function getOption(string $key): mixed
     {
         return $this->options[$key] ?? null;
     }
@@ -116,7 +102,7 @@ public function __toString(): string
      *
      * @since 5.0.0
      */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
     {
         return array_key_exists($offset, $this->options);
     }
@@ -134,7 +120,7 @@ public function offsetExists($offset): bool
      *
      * @since 5.0.0
      */
-    public function offsetGet($offset)
+    public function offsetGet(mixed $offset): mixed
     {
         return $this->options[$offset] ?? null;
     }
@@ -155,7 +141,7 @@ public function offsetGet($offset)
      *
      * @since 5.0.0
      */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
     {
         $this->options[$offset] = $value;
     }
@@ -173,12 +159,12 @@ public function offsetSet($offset, $value): void
      *
      * @since 5.0.0
      */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
     {
         unset($this->options[$offset]);
     }
 
-    private static function sanitize($input)
+    private static function sanitize(mixed $input): mixed
     {
         if (is_array($input)) {
             foreach ($input as $key => $value) {
diff --git a/src/Model/Response/PushResponse.php b/src/Model/Response/PushResponse.php
index a3aeb26..bd569ce 100644
--- a/src/Model/Response/PushResponse.php
+++ b/src/Model/Response/PushResponse.php
@@ -13,24 +13,13 @@ final class PushResponse
     const PAYLOAD_SIZE_TOO_LARGE = 413;
     const TOO_MANY_REQUESTS = 429;
 
-    /**
-     * @var int
-     */
-    private $statusCode;
-
-    /**
-     * @var UserSubscriptionInterface
-     */
-    private $subscription;
-
     /**
      * WebPushResponse constructor.
      */
-    public function __construct(UserSubscriptionInterface $subscription, int $statusCode)
-    {
-        $this->subscription = $subscription;
-        $this->statusCode = $statusCode;
-    }
+    public function __construct(
+        private UserSubscriptionInterface $subscription,
+        private int $statusCode,
+    ) {}
 
     public function getSubscription(): UserSubscriptionInterface
     {
diff --git a/src/Model/Subscription/UserSubscriptionManagerRegistry.php b/src/Model/Subscription/UserSubscriptionManagerRegistry.php
index b507c9f..a735451 100644
--- a/src/Model/Subscription/UserSubscriptionManagerRegistry.php
+++ b/src/Model/Subscription/UserSubscriptionManagerRegistry.php
@@ -12,12 +12,12 @@ final class UserSubscriptionManagerRegistry implements UserSubscriptionManagerIn
     /**
      * @var UserSubscriptionManagerInterface[]
      */
-    private $registry = [];
+    private array $registry = [];
 
     /**
      * @throws \InvalidArgumentException
      */
-    public function register(string $userClass, UserSubscriptionManagerInterface $userSubscriptionManager)
+    public function register(string $userClass, UserSubscriptionManagerInterface $userSubscriptionManager): void
     {
         if (!is_a($userClass, UserInterface::class, true)) {
             throw new \InvalidArgumentException(sprintf('Expected class implementing %s, %s given', UserInterface::class, $userClass));
@@ -42,7 +42,7 @@ public function register(string $userClass, UserSubscriptionManagerInterface $us
      * @throws \InvalidArgumentException
      * @throws \Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException
      */
-    public function getManager($userClass): UserSubscriptionManagerInterface
+    public function getManager(UserInterface|string $userClass): UserSubscriptionManagerInterface
     {
         if (!is_a($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)));
diff --git a/src/Twig/WebPushTwigExtension.php b/src/Twig/WebPushTwigExtension.php
index 65957ab..691143f 100644
--- a/src/Twig/WebPushTwigExtension.php
+++ b/src/Twig/WebPushTwigExtension.php
@@ -7,15 +7,9 @@
 
 final class WebPushTwigExtension extends AbstractExtension implements GlobalsInterface
 {
-    /**
-     * @var string
-     */
-    private $publicKey;
-
-    public function __construct(?string $publicKey)
-    {
-        $this->publicKey = $publicKey;
-    }
+    public function __construct(
+        private ?string $publicKey,
+    ) {}
 
     /**
      * {@inheritdoc}