diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5941407..7add214 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -22,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ["8.0", "8.1", "8.2", "8.3"]
+        php: ["8.1", "8.2", "8.3"]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/composer.json b/composer.json
index 4a6942f..3b1eecb 100644
--- a/composer.json
+++ b/composer.json
@@ -21,13 +21,13 @@
     },
     "minimum-stability": "stable",
     "require": {
-        "php": "^8.0",
+        "php": "^8.1",
         "behat/behat": "^3.8.0",
         "rpkamp/mailhog-client": "^2.0",
-        "symfony/dependency-injection": "^4.4 || ^5.4 || ^6.0",
+        "symfony/dependency-injection": "^6.4 || ^7.0",
         "psr-discovery/http-client-implementations": "^1.0",
         "psr-discovery/http-factory-implementations": "^1.0",
-        "symfony/http-client": "^5.4 || ^6.4"
+        "symfony/http-client": "^6.4 || ^7.0"
     },
     "require-dev": {
         "guzzlehttp/psr7": "^1.6",
diff --git a/src/ServiceContainer/MailhogExtension.php b/src/ServiceContainer/MailhogExtension.php
index 1ca40f8..cff9a8c 100644
--- a/src/ServiceContainer/MailhogExtension.php
+++ b/src/ServiceContainer/MailhogExtension.php
@@ -21,8 +21,6 @@
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
 
-use function method_exists;
-
 /**
  * This class configures a lot of services, so needs access
  * to a lot of classes. Therefore high coupling is allowed here.
@@ -69,7 +67,6 @@ private function registerHttpClient(ContainerBuilder $container): void
     {
         $httpClient = new Definition(ClientInterface::class);
         $httpClient->setFactory([Discover::class, 'httpClient']);
-        $this->markServicePrivate($httpClient);
 
         $container->setDefinition('mailhog.http_client', $httpClient);
     }
@@ -78,7 +75,6 @@ private function registerHttpMessageFactory(ContainerBuilder $container): void
     {
         $httpRequestFactory = new Definition(RequestFactoryInterface::class);
         $httpRequestFactory->setFactory([Discover::class, 'httpRequestFactory']);
-        $this->markServicePrivate($httpRequestFactory);
 
         $container->setDefinition('mailhog.http_request_factory', $httpRequestFactory);
     }
@@ -87,7 +83,6 @@ private function registerHttpStreamFactory(ContainerBuilder $container): void
     {
         $httpStreamFactory = new Definition(StreamFactoryInterface::class);
         $httpStreamFactory->setFactory([Discover::class, 'httpStreamFactory']);
-        $this->markServicePrivate($httpStreamFactory);
 
         $container->setDefinition('mailhog.http_stream_factory', $httpStreamFactory);
     }
@@ -100,7 +95,7 @@ private function registerMailhogClient(ContainerBuilder $container): void
             new Reference('mailhog.http_stream_factory'),
             '%mailhog.base_url%',
         ]);
-        $this->markServicePublic($mailhogClient);
+        $mailhogClient->setPublic(true);
 
         $container->setDefinition('mailhog.client', $mailhogClient);
     }
@@ -112,14 +107,12 @@ private function registerContextInitializer(ContainerBuilder $container): void
         ]);
 
         $contextInitializer->addTag(ContextExtension::INITIALIZER_TAG, ['priority' => 0]);
-        $this->markServicePrivate($contextInitializer);
         $container->setDefinition('mailhog.context_initializer', $contextInitializer);
     }
 
     private function registerOpenedEmailStorage(ContainerBuilder $container): void
     {
         $openedEmailStorage = new Definition(OpenedEmailStorage::class);
-        $this->markServicePrivate($openedEmailStorage);
 
         $container->setDefinition('mailhog.opened_email_storage', $openedEmailStorage);
     }
@@ -130,7 +123,6 @@ private function registerOpenedEmailStorageContextInitializer(ContainerBuilder $
             new Reference('mailhog.opened_email_storage'),
         ]);
         $openMailInitializer->addTag(ContextExtension::INITIALIZER_TAG, ['priority' => 0]);
-        $this->markServicePrivate($openMailInitializer);
 
         $container->setDefinition('mailhog.opened_email_storage.context_initializer', $openMailInitializer);
     }
@@ -142,33 +134,10 @@ private function registerPurgeListener(ContainerBuilder $container): void
             '%mailhog.purge_tag%',
         ]);
         $listener->addTag(EventDispatcherExtension::SUBSCRIBER_TAG, ['priority' => 0]);
-        $this->markServicePrivate($listener);
 
         $container->setDefinition('mailhog.purge_listener', $listener);
     }
 
-    private function markServicePrivate(Definition $definition): void
-    {
-        if (!method_exists($definition, 'setPrivate')) {
-            // symfony/dependency-injection >= 3.4 where
-            // all services are private by default
-            return;
-        }
-
-        $definition->setPrivate(true);
-    }
-
-    public function markServicePublic(Definition $definition): void
-    {
-        if (!method_exists($definition, 'setPublic')) {
-            // symfony/dependency-injection < 3.4 where
-            // all services are public by default
-            return;
-        }
-
-        $definition->setPublic(true);
-    }
-
     public function process(ContainerBuilder $container): void
     {
     }
diff --git a/tests/ServiceContainer/MailhogExtensionTest.php b/tests/ServiceContainer/MailhogExtensionTest.php
index 8240736..8b074fd 100644
--- a/tests/ServiceContainer/MailhogExtensionTest.php
+++ b/tests/ServiceContainer/MailhogExtensionTest.php
@@ -5,8 +5,6 @@
 
 use Behat\Behat\Context\ServiceContainer\ContextExtension;
 use Behat\Testwork\EventDispatcher\ServiceContainer\EventDispatcherExtension;
-use Http\Client\HttpClient;
-use Http\Message\MessageFactory;
 use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\RequestFactoryInterface;
 use Psr\Http\Message\StreamFactoryInterface;
@@ -19,7 +17,6 @@
 use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\HttpClient\Psr18Client;
-use Symfony\Contracts\HttpClient\HttpClientInterface;
 
 final class MailhogExtensionTest extends TestCase
 {