diff --git a/CHANGELOG.md b/CHANGELOG.md
index 772f5071..87262ce7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+6.2.7
+-----
+
+ * [BC BREAK] The following data providers for `TransportFactoryTestCase` are now static:
+  `supportsProvider()`, `createProvider()`, `unsupportedSchemeProvider()`and `incompleteDsnProvider()`
+
 6.2
 ---
 
diff --git a/LICENSE b/LICENSE
index 5c7ba055..f37c76b5 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2019-2023 Fabien Potencier
+Copyright (c) 2019-present Fabien Potencier
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/Test/TransportFactoryTestCase.php b/Test/TransportFactoryTestCase.php
index 1cf22e9b..7bcd8989 100644
--- a/Test/TransportFactoryTestCase.php
+++ b/Test/TransportFactoryTestCase.php
@@ -37,16 +37,16 @@ abstract class TransportFactoryTestCase extends TestCase
 
     abstract public function getFactory(): TransportFactoryInterface;
 
-    abstract public function supportsProvider(): iterable;
+    abstract public static function supportsProvider(): iterable;
 
-    abstract public function createProvider(): iterable;
+    abstract public static function createProvider(): iterable;
 
-    public function unsupportedSchemeProvider(): iterable
+    public static function unsupportedSchemeProvider(): iterable
     {
         return [];
     }
 
-    public function incompleteDsnProvider(): iterable
+    public static function incompleteDsnProvider(): iterable
     {
         return [];
     }
diff --git a/Tests/EventListener/MessageListenerTest.php b/Tests/EventListener/MessageListenerTest.php
index 2b2e5dfe..5f5def70 100644
--- a/Tests/EventListener/MessageListenerTest.php
+++ b/Tests/EventListener/MessageListenerTest.php
@@ -36,7 +36,7 @@ public function testHeaders(Headers $initialHeaders, Headers $defaultHeaders, He
         $this->assertEquals($expectedHeaders, $event->getMessage()->getHeaders());
     }
 
-    public function provideHeaders(): iterable
+    public static function provideHeaders(): iterable
     {
         $initialHeaders = new Headers();
         $defaultHeaders = (new Headers())
diff --git a/Tests/Exception/UnsupportedSchemeExceptionTest.php b/Tests/Exception/UnsupportedSchemeExceptionTest.php
index 56226dcd..445f028a 100644
--- a/Tests/Exception/UnsupportedSchemeExceptionTest.php
+++ b/Tests/Exception/UnsupportedSchemeExceptionTest.php
@@ -61,7 +61,7 @@ public function testMessageWhereSchemeIsPartOfSchemeToPackageMap(string $scheme,
         );
     }
 
-    public function messageWhereSchemeIsPartOfSchemeToPackageMapProvider(): \Generator
+    public static function messageWhereSchemeIsPartOfSchemeToPackageMapProvider(): \Generator
     {
         yield ['gmail', 'symfony/google-mailer'];
         yield ['infobip', 'symfony/infobip-mailer'];
@@ -86,7 +86,7 @@ public function testMessageWhereSchemeIsNotPartOfSchemeToPackageMap(string $expe
         );
     }
 
-    public function messageWhereSchemeIsNotPartOfSchemeToPackageMapProvider(): \Generator
+    public static function messageWhereSchemeIsNotPartOfSchemeToPackageMapProvider(): \Generator
     {
         yield [
             'The "somethingElse" scheme is not supported.',
diff --git a/Tests/Transport/DsnTest.php b/Tests/Transport/DsnTest.php
index 2816333f..f3c0a0bc 100644
--- a/Tests/Transport/DsnTest.php
+++ b/Tests/Transport/DsnTest.php
@@ -45,7 +45,7 @@ public function testInvalidDsn(string $dsn, string $exceptionMessage)
         Dsn::fromString($dsn);
     }
 
-    public function fromStringProvider(): iterable
+    public static function fromStringProvider(): iterable
     {
         yield 'simple smtp without user and pass' => [
             'smtp://example.com',
@@ -88,7 +88,7 @@ public function fromStringProvider(): iterable
         ];
     }
 
-    public function invalidDsnProvider(): iterable
+    public static function invalidDsnProvider(): iterable
     {
         yield [
             'some://',
diff --git a/Tests/Transport/NativeTransportFactoryTest.php b/Tests/Transport/NativeTransportFactoryTest.php
index 556a01ac..c253b4c7 100644
--- a/Tests/Transport/NativeTransportFactoryTest.php
+++ b/Tests/Transport/NativeTransportFactoryTest.php
@@ -47,7 +47,7 @@ function ini_get(\$key)
     public function testCreateWithNotSupportedScheme()
     {
         $this->expectException(UnsupportedSchemeException::class);
-        $this->expectErrorMessageMatches('#The ".*" scheme is not supported#');
+        $this->expectExceptionMessage('The "sendmail" scheme is not supported');
 
         $sut = new NativeTransportFactory();
         $sut->create(Dsn::fromString('sendmail://default'));
@@ -66,7 +66,7 @@ public function testCreateSendmailWithNoSendmailPath()
         $sut->create(Dsn::fromString('native://default'));
     }
 
-    public function provideCreateSendmailWithNoHostOrNoPort(): \Generator
+    public static function provideCreateSendmailWithNoHostOrNoPort(): \Generator
     {
         yield ['native://default', '', '', ''];
         yield ['native://default', '', 'localhost', ''];
@@ -95,7 +95,7 @@ public function testCreateSendmailWithNoHostOrNoPort(string $dsn, string $sendma
         $sut->create(Dsn::fromString($dsn));
     }
 
-    public function provideCreate(): \Generator
+    public static function provideCreate(): \Generator
     {
         yield ['native://default', '/usr/sbin/sendmail -t -i', '', '', new SendmailTransport('/usr/sbin/sendmail -t -i')];
 
diff --git a/Tests/Transport/NullTransportFactoryTest.php b/Tests/Transport/NullTransportFactoryTest.php
index 9b39a614..b28935a7 100644
--- a/Tests/Transport/NullTransportFactoryTest.php
+++ b/Tests/Transport/NullTransportFactoryTest.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Mailer\Tests\Transport;
 
+use Psr\Log\NullLogger;
+use Symfony\Component\HttpClient\MockHttpClient;
 use Symfony\Component\Mailer\Test\TransportFactoryTestCase;
 use Symfony\Component\Mailer\Transport\Dsn;
 use Symfony\Component\Mailer\Transport\NullTransport;
@@ -21,10 +23,10 @@ class NullTransportFactoryTest extends TransportFactoryTestCase
 {
     public function getFactory(): TransportFactoryInterface
     {
-        return new NullTransportFactory($this->getDispatcher(), $this->getClient(), $this->getLogger());
+        return new NullTransportFactory(null, new MockHttpClient(), new NullLogger());
     }
 
-    public function supportsProvider(): iterable
+    public static function supportsProvider(): iterable
     {
         yield [
             new Dsn('null', ''),
@@ -32,11 +34,11 @@ public function supportsProvider(): iterable
         ];
     }
 
-    public function createProvider(): iterable
+    public static function createProvider(): iterable
     {
         yield [
             new Dsn('null', 'null'),
-            new NullTransport($this->getDispatcher(), $this->getLogger()),
+            new NullTransport(null, new NullLogger()),
         ];
     }
 }
diff --git a/Tests/Transport/SendmailTransportFactoryTest.php b/Tests/Transport/SendmailTransportFactoryTest.php
index 55f893b0..a3d08f59 100644
--- a/Tests/Transport/SendmailTransportFactoryTest.php
+++ b/Tests/Transport/SendmailTransportFactoryTest.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Mailer\Tests\Transport;
 
+use Psr\Log\NullLogger;
+use Symfony\Component\HttpClient\MockHttpClient;
 use Symfony\Component\Mailer\Test\TransportFactoryTestCase;
 use Symfony\Component\Mailer\Transport\Dsn;
 use Symfony\Component\Mailer\Transport\SendmailTransport;
@@ -21,10 +23,10 @@ class SendmailTransportFactoryTest extends TransportFactoryTestCase
 {
     public function getFactory(): TransportFactoryInterface
     {
-        return new SendmailTransportFactory($this->getDispatcher(), $this->getClient(), $this->getLogger());
+        return new SendmailTransportFactory(null, new MockHttpClient(), new NullLogger());
     }
 
-    public function supportsProvider(): iterable
+    public static function supportsProvider(): iterable
     {
         yield [
             new Dsn('sendmail+smtp', 'default'),
@@ -32,20 +34,20 @@ public function supportsProvider(): iterable
         ];
     }
 
-    public function createProvider(): iterable
+    public static function createProvider(): iterable
     {
         yield [
             new Dsn('sendmail+smtp', 'default'),
-            new SendmailTransport(null, $this->getDispatcher(), $this->getLogger()),
+            new SendmailTransport(null, null, new NullLogger()),
         ];
 
         yield [
             new Dsn('sendmail+smtp', 'default', null, null, null, ['command' => '/usr/sbin/sendmail -oi -t']),
-            new SendmailTransport('/usr/sbin/sendmail -oi -t', $this->getDispatcher(), $this->getLogger()),
+            new SendmailTransport('/usr/sbin/sendmail -oi -t', null, new NullLogger()),
         ];
     }
 
-    public function unsupportedSchemeProvider(): iterable
+    public static function unsupportedSchemeProvider(): iterable
     {
         yield [
             new Dsn('sendmail+http', 'default'),
diff --git a/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php b/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
index 7b1b52f4..bcdf669b 100644
--- a/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
+++ b/Tests/Transport/Smtp/EsmtpTransportFactoryTest.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Mailer\Tests\Transport\Smtp;
 
+use Psr\Log\NullLogger;
+use Symfony\Component\HttpClient\MockHttpClient;
 use Symfony\Component\Mailer\Test\TransportFactoryTestCase;
 use Symfony\Component\Mailer\Transport\Dsn;
 use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;
@@ -22,10 +24,10 @@ class EsmtpTransportFactoryTest extends TransportFactoryTestCase
 {
     public function getFactory(): TransportFactoryInterface
     {
-        return new EsmtpTransportFactory($this->getDispatcher(), $this->getClient(), $this->getLogger());
+        return new EsmtpTransportFactory(null, new MockHttpClient(), new NullLogger());
     }
 
-    public function supportsProvider(): iterable
+    public static function supportsProvider(): iterable
     {
         yield [
             new Dsn('smtp', 'example.com'),
@@ -43,19 +45,18 @@ public function supportsProvider(): iterable
         ];
     }
 
-    public function createProvider(): iterable
+    public static function createProvider(): iterable
     {
-        $eventDispatcher = $this->getDispatcher();
-        $logger = $this->getLogger();
+        $logger = new NullLogger();
 
-        $transport = new EsmtpTransport('localhost', 25, false, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('localhost', 25, false, null, $logger);
 
         yield [
             new Dsn('smtp', 'localhost'),
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 99, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 99, true, null, $logger);
         $transport->setUsername(self::USER);
         $transport->setPassword(self::PASSWORD);
 
@@ -64,21 +65,21 @@ public function createProvider(): iterable
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
 
         yield [
             new Dsn('smtps', 'example.com'),
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
 
         yield [
             new Dsn('smtps', 'example.com', '', '', 465),
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
         /** @var SocketStream $stream */
         $stream = $transport->getStream();
         $streamOptions = $stream->getStreamOptions();
@@ -101,14 +102,14 @@ public function createProvider(): iterable
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
 
         yield [
             Dsn::fromString('smtps://:@example.com?verify_peer='),
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
         $transport->setLocalDomain('example.com');
 
         yield [
@@ -116,7 +117,7 @@ public function createProvider(): iterable
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
         $transport->setMaxPerSecond(2.0);
 
         yield [
@@ -124,7 +125,7 @@ public function createProvider(): iterable
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
         $transport->setRestartThreshold(10, 1);
 
         yield [
@@ -132,7 +133,7 @@ public function createProvider(): iterable
             $transport,
         ];
 
-        $transport = new EsmtpTransport('example.com', 465, true, $eventDispatcher, $logger);
+        $transport = new EsmtpTransport('example.com', 465, true, null, $logger);
         $transport->setPingThreshold(10);
 
         yield [
diff --git a/Tests/Transport/Smtp/Stream/AbstractStreamTest.php b/Tests/Transport/Smtp/Stream/AbstractStreamTest.php
index cc901ccb..aeb2834c 100644
--- a/Tests/Transport/Smtp/Stream/AbstractStreamTest.php
+++ b/Tests/Transport/Smtp/Stream/AbstractStreamTest.php
@@ -29,7 +29,7 @@ public function testReplace(string $expected, string $from, string $to, array $c
         $this->assertSame($expected, $result);
     }
 
-    public function provideReplace()
+    public static function provideReplace()
     {
         yield ['ca', 'ab', 'c', ['a', 'b', 'a']];
         yield ['ac', 'ab', 'c', ['a', 'ab']];
diff --git a/Tests/TransportTest.php b/Tests/TransportTest.php
index 690b0eed..3ffd706c 100644
--- a/Tests/TransportTest.php
+++ b/Tests/TransportTest.php
@@ -34,7 +34,7 @@ public function testFromString(string $dsn, TransportInterface $transport)
         $this->assertEquals($transport, $transportFactory->fromString($dsn));
     }
 
-    public function fromStringProvider(): iterable
+    public static function fromStringProvider(): iterable
     {
         $transportA = new DummyTransport('a');
         $transportB = new DummyTransport('b');
@@ -68,7 +68,7 @@ public function testFromDsn(string $dsn, TransportInterface $transport)
         $this->assertEquals($transport, Transport::fromDsn($dsn));
     }
 
-    public function fromDsnProvider(): iterable
+    public static function fromDsnProvider(): iterable
     {
         yield 'multiple transports' => [
             'failover(smtp://a smtp://b)',
@@ -88,7 +88,7 @@ public function testFromWrongString(string $dsn, string $error)
         $transportFactory->fromString($dsn);
     }
 
-    public function fromWrongStringProvider(): iterable
+    public static function fromWrongStringProvider(): iterable
     {
         yield 'garbage at the end' => ['dummy://a some garbage here', 'The DSN has some garbage at the end: " some garbage here".'];
 
diff --git a/Transport/Smtp/SmtpTransport.php b/Transport/Smtp/SmtpTransport.php
index 675528ce..0f228191 100644
--- a/Transport/Smtp/SmtpTransport.php
+++ b/Transport/Smtp/SmtpTransport.php
@@ -246,6 +246,7 @@ protected function doSend(SentMessage $message): void
 
     /**
      * @internal since version 6.1, to be made private in 7.0
+     *
      * @final since version 6.1, to be made private in 7.0
      */
     protected function doHeloCommand(): void
diff --git a/Transport/Smtp/Stream/ProcessStream.php b/Transport/Smtp/Stream/ProcessStream.php
index d178bc8b..dc3b8f05 100644
--- a/Transport/Smtp/Stream/ProcessStream.php
+++ b/Transport/Smtp/Stream/ProcessStream.php
@@ -35,7 +35,7 @@ public function initialize(): void
         $descriptorSpec = [
             0 => ['pipe', 'r'],
             1 => ['pipe', 'w'],
-            2 => ['pipe', 'w'],
+            2 => ['pipe', '\\' === \DIRECTORY_SEPARATOR ? 'a' : 'w'],
         ];
         $pipes = [];
         $this->stream = proc_open($this->command, $descriptorSpec, $pipes);
diff --git a/composer.json b/composer.json
index ded4309c..83fbecd9 100644
--- a/composer.json
+++ b/composer.json
@@ -26,7 +26,7 @@
     },
     "require-dev": {
         "symfony/console": "^5.4|^6.0",
-        "symfony/http-client-contracts": "^1.1|^2|^3",
+        "symfony/http-client": "^5.4|^6.0",
         "symfony/messenger": "^6.2",
         "symfony/twig-bridge": "^6.2"
     },