diff --git a/.github/workflows/grumphp.yaml b/.github/workflows/grumphp.yaml
index c379c26..e35e5b4 100644
--- a/.github/workflows/grumphp.yaml
+++ b/.github/workflows/grumphp.yaml
@@ -7,7 +7,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.1', '8.2', '8.3', '8.4']
+                php-versions: ['8.3', '8.4', '8.5']
                 composer-options: ['', '--prefer-lowest']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }} with ${{ matrix.composer-options }}
@@ -21,7 +21,7 @@ jobs:
                   tools: 'composer:v2'
                   extensions: pcov, mbstring, posix
             - name: Set env vars for latest PHP version
-              if: matrix.php-versions == '8.4'
+              if: matrix.php-versions == '8.5'
               run: |
                 export COMPOSER_IGNORE_PLATFORM_REQ=php+
                 export BOX_REQUIREMENT_CHECKER=0
@@ -34,7 +34,7 @@ jobs:
               id: composercache
               run: echo "::set-output name=dir::$(composer config cache-files-dir)"
             - name: Cache dependencies
-              uses: actions/cache@v2
+              uses: actions/cache@v4
               with:
                   path: ${{ steps.composercache.outputs.dir }}
                   key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
@@ -43,5 +43,6 @@ jobs:
               run: composer update --prefer-dist --no-progress --ignore-platform-req=php+ ${{ matrix.composer-options }}
             - name: Run the tests
               run: php vendor/bin/grumphp run --no-interaction
+              continue-on-error: ${{ matrix.php-versions == '8.5' }}
               env:
                 PHP_CS_FIXER_IGNORE_ENV: 1
diff --git a/composer.json b/composer.json
index 3ab162d..ce664e2 100644
--- a/composer.json
+++ b/composer.json
@@ -10,19 +10,19 @@
         }
     ],
     "require": {
-        "php": "~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
+        "php": "~8.3.0 || ~8.4.0 || ~8.5.0",
         "phpro/api-problem": "^1.0",
         "symfony/dependency-injection": "^5.4 || ^6.0 || ^7.0",
         "symfony/event-dispatcher": "^5.4 || ^6.0 || ^7.0",
         "symfony/http-kernel": "^6.4 || ^7.0"
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "^3.39",
         "matthiasnoback/symfony-dependency-injection-test": "^4.3",
-        "phpro/grumphp-shim": "^2.10",
-        "phpspec/prophecy-phpunit": "^2.0",
+        "php-cs-fixer/shim": "^3.88",
+        "phpro/grumphp-shim": "^2.17",
         "phpspec/prophecy": "^1.17",
-        "phpunit/phpunit": "^9.5",
+        "phpspec/prophecy-phpunit": "^2.0",
+        "phpunit/phpunit": "^12.4",
         "symfony/security-core": "^5.4 || ^6.0 || ^7.0"
     },
     "config": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 39ae7ee..fca43fb 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,8 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+        xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
         colors="true"
+        displayDetailsOnTestsThatTriggerWarnings="true"
+        failOnWarning="true"
+        failOnPhpunitWarning="true"
+        beStrictAboutOutputDuringTests="true"
 >
     <testsuites>
         <testsuite name="Unit">
@@ -10,12 +14,15 @@
         </testsuite>
     </testsuites>
 
-  <coverage processUncoveredFiles="true">
-      <include>
-          <directory suffix=".php">src</directory>
-      </include>
-      <report>
-          <clover outputFile="var/coverage.xml"/>
-      </report>
-  </coverage>
+    <source>
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </source>
+
+    <coverage includeUncoveredFiles="true">
+        <report>
+            <clover outputFile="var/coverage.xml"/>
+        </report>
+    </coverage>
 </phpunit>
diff --git a/test/ApiProblemBundleTest.php b/test/ApiProblemBundleTest.php
index de12e13..e675857 100644
--- a/test/ApiProblemBundleTest.php
+++ b/test/ApiProblemBundleTest.php
@@ -5,13 +5,15 @@
 namespace PhproTest\ApiProblemBundle;
 
 use Phpro\ApiProblemBundle\ApiProblemBundle;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
-/** @covers \Phpro\ApiProblemBundle\ApiProblemBundle */
+#[CoversClass(ApiProblemBundle::class)]
 class ApiProblemBundleTest extends TestCase
 {
-    /** @test */
+    #[Test]
     public function it_is_a_symfony_bundle(): void
     {
         $this->assertInstanceOf(Bundle::class, new ApiProblemBundle());
diff --git a/test/DependencyInjection/ApiProblemExtensionTest.php b/test/DependencyInjection/ApiProblemExtensionTest.php
index fada960..70c7cd9 100644
--- a/test/DependencyInjection/ApiProblemExtensionTest.php
+++ b/test/DependencyInjection/ApiProblemExtensionTest.php
@@ -8,11 +8,11 @@
 use Phpro\ApiProblemBundle\DependencyInjection\ApiProblemExtension;
 use Phpro\ApiProblemBundle\EventListener\JsonApiProblemExceptionListener;
 use Phpro\ApiProblemBundle\Transformer;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
 
-/**
- * @covers \Phpro\ApiProblemBundle\DependencyInjection\ApiProblemExtension
- */
+#[CoversClass(ApiProblemExtension::class)]
 class ApiProblemExtensionTest extends AbstractExtensionTestCase
 {
     private const TRANSFORMER_TAG = 'phpro.api_problem.exception_transformer';
@@ -22,7 +22,7 @@ protected function getContainerExtensions(): array
         return [new ApiProblemExtension()];
     }
 
-    /** @test */
+    #[Test]
     public function it_registers_json_exception_listener(): void
     {
         $this->load([]);
@@ -52,7 +52,7 @@ public function it_registers_json_exception_listener(): void
         );
     }
 
-    /** @test */
+    #[Test]
     public function it_contains_exception_transformers(): void
     {
         $this->load([]);
diff --git a/test/EventListener/JsonApiProblemExceptionListenerTest.php b/test/EventListener/JsonApiProblemExceptionListenerTest.php
index fef0e4c..5e2c0bf 100644
--- a/test/EventListener/JsonApiProblemExceptionListenerTest.php
+++ b/test/EventListener/JsonApiProblemExceptionListenerTest.php
@@ -13,6 +13,8 @@
 use Phpro\ApiProblem\Http\HttpApiProblem;
 use Phpro\ApiProblemBundle\EventListener\JsonApiProblemExceptionListener;
 use Phpro\ApiProblemBundle\Transformer\ExceptionTransformerInterface;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\PhpUnit\ProphecyTrait;
@@ -22,7 +24,7 @@
 use Symfony\Component\HttpKernel\Event\ExceptionEvent;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 
-/** @covers \Phpro\ApiProblemBundle\EventListener\JsonApiProblemExceptionListener */
+#[CoversClass(JsonApiProblemExceptionListener::class)]
 class JsonApiProblemExceptionListenerTest extends TestCase
 {
     use ProphecyTrait;
@@ -38,7 +40,7 @@ protected function setUp(): void
         $this->exceptionTransformer->accepts(Argument::any())->willReturn(false);
     }
 
-    /** @test */
+    #[Test]
     public function it_does_nothing_on_non_json_requests(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -53,7 +55,7 @@ public function it_does_nothing_on_non_json_requests(): void
         $this->assertNull($event->getResponse());
     }
 
-    /** @test */
+    #[Test]
     public function it_runs_on_json_route_formats(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -69,7 +71,7 @@ public function it_runs_on_json_route_formats(): void
         $this->assertApiProblemWithResponseBody($event, 500, $this->parseDataForException($exception));
     }
 
-    /** @test */
+    #[Test]
     public function it_runs_on_json_content_types(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -84,7 +86,7 @@ public function it_runs_on_json_content_types(): void
         $this->assertApiProblemWithResponseBody($event, 500, $this->parseDataForException($exception));
     }
 
-    /** @test */
+    #[Test]
     public function it_runs_on_json_accept_header(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -99,7 +101,7 @@ public function it_runs_on_json_accept_header(): void
         $this->assertApiProblemWithResponseBody($event, 500, $this->parseDataForException($exception));
     }
 
-    /** @test */
+    #[Test]
     public function it_parses_an_api_problem_response(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -114,7 +116,7 @@ public function it_parses_an_api_problem_response(): void
         $this->assertApiProblemWithResponseBody($event, 500, $this->parseDataForException($exception));
     }
 
-    /** @test */
+    #[Test]
     public function it_uses_an_exception_transformer(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -134,7 +136,7 @@ public function it_uses_an_exception_transformer(): void
         $this->assertApiProblemWithResponseBody($event, 400, []);
     }
 
-    /** @test */
+    #[Test]
     public function it_returns_the_status_code_from_the_api_problem(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), false);
@@ -154,7 +156,7 @@ public function it_returns_the_status_code_from_the_api_problem(): void
         $this->assertApiProblemWithResponseBody($event, 123, ['status' => 123]);
     }
 
-    /** @test */
+    #[Test]
     public function it_parses_a_debuggable_api_problem_response(): void
     {
         $listener = new JsonApiProblemExceptionListener($this->exceptionTransformer->reveal(), true);
diff --git a/test/Exception/ApiProblemHttpExceptionTest.php b/test/Exception/ApiProblemHttpExceptionTest.php
index f7ddd77..5228942 100644
--- a/test/Exception/ApiProblemHttpExceptionTest.php
+++ b/test/Exception/ApiProblemHttpExceptionTest.php
@@ -7,6 +7,7 @@
 use Phpro\ApiProblem\Http\HttpApiProblem;
 use Phpro\ApiProblemBundle\Exception\ApiProblemHttpException;
 use Phpro\ApiProblemBundle\Transformer\ApiProblemExceptionTransformer;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
 use Prophecy\Prophecy\ObjectProphecy;
@@ -27,7 +28,7 @@ protected function setUp(): void/* The :void return type declaration that should
         $this->apiProblem->toArray()->willReturn([]);
     }
 
-    /** @test */
+    #[Test]
     public function it_is_accepted_by_the__api_problem_exception_transformer(): void
     {
         $transformer = new ApiProblemExceptionTransformer();
@@ -35,7 +36,7 @@ public function it_is_accepted_by_the__api_problem_exception_transformer(): void
         $this->assertTrue($transformer->accepts(new ApiProblemHttpException($this->apiProblem->reveal())));
     }
 
-    /** @test */
+    #[Test]
     public function it_is_an_instance_of__http_exception(): void
     {
         $exception = new ApiProblemHttpException($this->apiProblem->reveal());
@@ -43,7 +44,7 @@ public function it_is_an_instance_of__http_exception(): void
         $this->assertInstanceOf(HttpException::class, $exception);
     }
 
-    /** @test */
+    #[Test]
     public function it_contains_an_api_problem(): void
     {
         $apiProblem = $this->apiProblem->reveal();
@@ -52,7 +53,7 @@ public function it_contains_an_api_problem(): void
         $this->assertEquals($apiProblem, $exception->getApiProblem());
     }
 
-    /** @test */
+    #[Test]
     public function it_returns_the_correct_http_headers(): void
     {
         $exception = new ApiProblemHttpException($this->apiProblem->reveal());
@@ -60,7 +61,7 @@ public function it_returns_the_correct_http_headers(): void
         $this->assertEquals(['Content-Type' => 'application/problem+json'], $exception->getHeaders());
     }
 
-    /** @test */
+    #[Test]
     public function it_returns_the_correct_default_http_statuscode(): void
     {
         $exception = new ApiProblemHttpException($this->apiProblem->reveal());
@@ -68,7 +69,7 @@ public function it_returns_the_correct_default_http_statuscode(): void
         $this->assertEquals(400, $exception->getStatusCode());
     }
 
-    /** @test */
+    #[Test]
     public function it_returns_the_correct_specified_http_statuscode(): void
     {
         $this->apiProblem->toArray()->willReturn(['status' => 401]);
diff --git a/test/Transformer/ApiProblemExceptionTransformerTest.php b/test/Transformer/ApiProblemExceptionTransformerTest.php
index 43eced2..b354eb5 100644
--- a/test/Transformer/ApiProblemExceptionTransformerTest.php
+++ b/test/Transformer/ApiProblemExceptionTransformerTest.php
@@ -9,13 +9,13 @@
 use Phpro\ApiProblem\Exception\ApiProblemException;
 use Phpro\ApiProblemBundle\Transformer\ApiProblemExceptionTransformer;
 use Phpro\ApiProblemBundle\Transformer\ExceptionTransformerInterface;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
 use Prophecy\Prophecy\ObjectProphecy;
 
-/**
- * @covers \Phpro\ApiProblemBundle\Transformer\ApiProblemExceptionTransformer
- */
+#[CoversClass(ApiProblemExceptionTransformer::class)]
 class ApiProblemExceptionTransformerTest extends TestCase
 {
     use ProphecyTrait;
@@ -31,14 +31,14 @@ protected function setUp(): void/* The :void return type declaration that should
         $this->apiProblem->toArray()->willReturn([]);
     }
 
-    /** @test */
+    #[Test]
     public function it_is_an_exception_transformer(): void
     {
         $transformer = new ApiProblemExceptionTransformer();
         $this->assertInstanceOf(ExceptionTransformerInterface::class, $transformer);
     }
 
-    /** @test */
+    #[Test]
     public function it_accepts_api_problem_exceptions(): void
     {
         $transformer = new ApiProblemExceptionTransformer();
@@ -47,7 +47,7 @@ public function it_accepts_api_problem_exceptions(): void
         $this->assertFalse($transformer->accepts(new Exception()));
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_exception_to_api_problem(): void
     {
         $transformer = new ApiProblemExceptionTransformer();
diff --git a/test/Transformer/ChainTest.php b/test/Transformer/ChainTest.php
index e5a8545..eb1fc4f 100644
--- a/test/Transformer/ChainTest.php
+++ b/test/Transformer/ChainTest.php
@@ -9,33 +9,33 @@
 use Phpro\ApiProblem\Http\ExceptionApiProblem;
 use Phpro\ApiProblemBundle\Transformer\Chain;
 use Phpro\ApiProblemBundle\Transformer\ExceptionTransformerInterface;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\PhpUnit\ProphecyTrait;
 use Prophecy\Prophecy\ObjectProphecy;
 
-/**
- * @covers \Phpro\ApiProblemBundle\Transformer\Chain
- */
+#[CoversClass(Chain::class)]
 class ChainTest extends TestCase
 {
     use ProphecyTrait;
 
-    /** @test */
+    #[Test]
     public function it_is_an_exception_transformer(): void
     {
         $transformer = new Chain([]);
         $this->assertInstanceOf(ExceptionTransformerInterface::class, $transformer);
     }
 
-    /** @test */
+    #[Test]
     public function it_accepts_any_exception(): void
     {
         $transformer = new Chain([]);
         $this->assertTrue($transformer->accepts(new Exception()));
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_with_first_acceptable_transformer(): void
     {
         $transformer = new Chain([
@@ -47,7 +47,7 @@ public function it_transforms_with_first_acceptable_transformer(): void
         $this->assertEquals($apiProblem1, $transformer->transform(new Exception()));
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_to_basic_exception_problem_when_no_transformer_matches(): void
     {
         $transformer = new Chain([$this->mockTransformer(false)]);
diff --git a/test/Transformer/HttpExceptionTransformerTest.php b/test/Transformer/HttpExceptionTransformerTest.php
index b58fe14..ae37446 100644
--- a/test/Transformer/HttpExceptionTransformerTest.php
+++ b/test/Transformer/HttpExceptionTransformerTest.php
@@ -9,22 +9,22 @@
 use Phpro\ApiProblem\Http\HttpApiProblem;
 use Phpro\ApiProblemBundle\Transformer\ExceptionTransformerInterface;
 use Phpro\ApiProblemBundle\Transformer\HttpExceptionTransformer;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpKernel\Exception\HttpException;
 
-/**
- * @covers \Phpro\ApiProblemBundle\Transformer\HttpExceptionTransformer
- */
+#[CoversClass(HttpExceptionTransformer::class)]
 class HttpExceptionTransformerTest extends TestCase
 {
-    /** @test */
+    #[Test]
     public function it_is_an_exception_transformer(): void
     {
         $transformer = new HttpExceptionTransformer();
         $this->assertInstanceOf(ExceptionTransformerInterface::class, $transformer);
     }
 
-    /** @test */
+    #[Test]
     public function it_accepts_api_problem_exceptions(): void
     {
         $transformer = new HttpExceptionTransformer();
@@ -33,7 +33,7 @@ public function it_accepts_api_problem_exceptions(): void
         $this->assertFalse($transformer->accepts(new Exception()));
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_exception_to_api_problem(): void
     {
         $transformer = new HttpExceptionTransformer();
diff --git a/test/Transformer/SecurityExceptionTransformerTest.php b/test/Transformer/SecurityExceptionTransformerTest.php
index 5e81857..046e0f0 100644
--- a/test/Transformer/SecurityExceptionTransformerTest.php
+++ b/test/Transformer/SecurityExceptionTransformerTest.php
@@ -10,24 +10,24 @@
 use Phpro\ApiProblem\Http\UnauthorizedProblem;
 use Phpro\ApiProblemBundle\Transformer\ExceptionTransformerInterface;
 use Phpro\ApiProblemBundle\Transformer\SecurityExceptionTransformer;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\Exception\AccessDeniedException;
 use Symfony\Component\Security\Core\Exception\AuthenticationException;
 use Symfony\Component\Security\Core\Exception\RuntimeException;
 
-/**
- * @covers \Phpro\ApiProblemBundle\Transformer\SecurityExceptionTransformer
- */
+#[CoversClass(SecurityExceptionTransformer::class)]
 class SecurityExceptionTransformerTest extends TestCase
 {
-    /** @test */
+    #[Test]
     public function it_is_an_exception_transformer(): void
     {
         $transformer = new SecurityExceptionTransformer();
         $this->assertInstanceOf(ExceptionTransformerInterface::class, $transformer);
     }
 
-    /** @test */
+    #[Test]
     public function it_accepts_api_problem_exceptions(): void
     {
         $transformer = new SecurityExceptionTransformer();
@@ -36,7 +36,7 @@ public function it_accepts_api_problem_exceptions(): void
         $this->assertFalse($transformer->accepts(new Exception()));
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_authentication_exception_to_api_problem(): void
     {
         $transformer = new SecurityExceptionTransformer();
@@ -52,7 +52,7 @@ public function it_transforms_authentication_exception_to_api_problem(): void
         ], $apiProblem->toArray());
     }
 
-    /** @test */
+    #[Test]
     public function it_transforms_other_security_exceptions_to_api_problem(): void
     {
         $transformer = new SecurityExceptionTransformer();