diff --git a/.github/ISSUE_TEMPLATE.md b/.github/ISSUE_TEMPLATE.md
index d04471f..3dd9238 100644
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -39,5 +39,5 @@ $ composer show --latest 'symfony-cmf/*'
     If it's an error message or piece of code, use code block tags,
     and make sure you provide the whole stack trace(s),
     not just the first error message you can see.
-    More details here: https://github.com/symfony-cmf/Testing/blob/master/CONTRIBUTING.md#issues
+    More details here: https://github.com/symfony-cmf/Testing/blob/5.x/CONTRIBUTING.md#issues
 -->
diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 0d8f7f7..8505ce9 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -1,6 +1,6 @@
 | Q             | A
 | ------------- | ---
-| Branch?       | "master" for new features / the branch of the current release for fixes
+| Branch?       | branch of the next release for new features / the branch of the current release for fixes
 | Bug fix?      | yes/no
 | New feature?  | yes/no
 | BC breaks?    | yes/no
diff --git a/.github/workflows/test-application.yaml b/.github/workflows/test-application.yaml
index 22ce986..680d890 100644
--- a/.github/workflows/test-application.yaml
+++ b/.github/workflows/test-application.yaml
@@ -11,7 +11,7 @@ on:
 jobs:
     test:
         name: 'PHP ${{ matrix.php-version }}, Symfony ${{ matrix.symfony-version }} ${{ matrix.dependencies}}'
-        runs-on: ubuntu-20.04
+        runs-on: ubuntu-latest
 
         env:
             SYMFONY_DEPRECATIONS_HELPER: weak
@@ -27,6 +27,8 @@ jobs:
               - php-version: '8.1'
               - php-version: '8.2'
               - php-version: '8.3'
+              - php-version: '8.4'
+              - php-version: '8.5'
 
         steps:
             - name: Checkout project
diff --git a/bootstrap/kernel_bootstrap.php b/bootstrap/kernel_bootstrap.php
index 5506341..950ac83 100644
--- a/bootstrap/kernel_bootstrap.php
+++ b/bootstrap/kernel_bootstrap.php
@@ -18,13 +18,13 @@
 $phpUnitFile = $rootDir.'/phpunit.xml.dist';
 
 if (!file_exists($phpUnitFile)) {
-    throw new \Exception(sprintf(
+    throw new Exception(sprintf(
         'Cannot find phpunit.xml.dist file in "%s"',
         $phpUnitFile
     ));
 }
 
-$xml = new \SimpleXMLElement(file_get_contents($phpUnitFile));
+$xml = new SimpleXMLElement(file_get_contents($phpUnitFile));
 
 $envClass = $xml->xpath("//php/env[@name='KERNEL_CLASS']");
 if (count($envClass)) {
@@ -32,7 +32,7 @@
 } else {
     $envDir = $xml->xpath("//php/server[@name='KERNEL_DIR']");
     if (!count($envDir)) {
-        throw new \Exception(
+        throw new Exception(
             'KERNEL_CLASS must be set via <env name"KERNEL_CLASS" value="..."/>'
         );
     }
@@ -40,7 +40,7 @@
     $kernelFile = $rootDir.'/'.$envDir[0]['value'].'/'.$kernelClass.'.php';
 
     if (!file_exists($kernelFile)) {
-        throw new \Exception(sprintf(
+        throw new Exception(sprintf(
             'Cannot find kernel file "%s"',
             $kernelFile
         ));
diff --git a/composer.json b/composer.json
index 07dd10e..09b891e 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     "require": {
         "php": "^8.1",
         "doctrine/data-fixtures": "^1.2",
-        "symfony/browser-kit": "^6.4 || ^7.0"
+        "symfony/browser-kit": "^6.4 || ^7.0 || ^8.0"
     },
     "require-dev": {
         "ext-dom": "*",
@@ -19,14 +19,14 @@
         "doctrine/phpcr-odm": "^2.0",
         "doctrine/phpcr-bundle": "^3.0",
         "jackalope/jackalope-doctrine-dbal": "^2.0",
-        "symfony/console": "^6.4 || ^7.0",
-        "symfony/dependency-injection": "^6.4 || ^7.0",
-        "symfony/doctrine-bridge": "^6.4 || ^7.0",
-        "symfony/framework-bundle": "^6.4 || ^7.0",
-        "symfony/http-kernel": "^6.4 || ^7.0",
+        "symfony/console": "^6.4 || ^7.0 || ^8.0",
+        "symfony/dependency-injection": "^6.4 || ^7.0 || ^8.0",
+        "symfony/doctrine-bridge": "^6.4 || ^7.0 || ^8.0",
+        "symfony/framework-bundle": "^6.4 || ^7.0 || ^8.0",
+        "symfony/http-kernel": "^6.4 || ^7.0 || ^8.0",
         "symfony/monolog-bundle": "^3.5",
-        "symfony/security-bundle": "^6.4 || ^7.0",
-        "symfony/twig-bundle": "^6.4 || ^7.0",
+        "symfony/security-bundle": "^6.4 || ^7.0 || ^8.0",
+        "symfony/twig-bundle": "^6.4 || ^7.0 || ^8.0",
         "symfony/phpunit-bridge": "^7.0.3"
     },
     "conflict": {
diff --git a/resources/config/dist/security.php b/resources/config/dist/security.php
index 57d1dc1..4c8ddb3 100644
--- a/resources/config/dist/security.php
+++ b/resources/config/dist/security.php
@@ -40,7 +40,7 @@
     ],
 ];
 
-if (class_exists(\Symfony\Component\Security\Core\Security::class)) {
+if (class_exists(Symfony\Component\Security\Core\Security::class)) {
     // Symfony 6 but not 7
     $config['enable_authenticator_manager'] = true;
 }
diff --git a/src/Functional/BaseTestCase.php b/src/Functional/BaseTestCase.php
index 3a77b68..aeb62ca 100644
--- a/src/Functional/BaseTestCase.php
+++ b/src/Functional/BaseTestCase.php
@@ -124,7 +124,7 @@ protected function getDbManager(string $type): PhpcrDecorator|PHPCR|ORM
             return $this->dbManagers[$type];
         }
 
-        $className = sprintf(
+        $className = \sprintf(
             'Symfony\Cmf\Component\Testing\Functional\DbManager\%s',
             $type
         );
@@ -134,7 +134,7 @@ protected function getDbManager(string $type): PhpcrDecorator|PHPCR|ORM
         }
 
         if (!class_exists($className)) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new \InvalidArgumentException(\sprintf(
                 'Test DBManager "%s" does not exist.',
                 $className
             ));
diff --git a/src/Functional/DbManager/ORM.php b/src/Functional/DbManager/ORM.php
index c72fd14..c3a8b91 100644
--- a/src/Functional/DbManager/ORM.php
+++ b/src/Functional/DbManager/ORM.php
@@ -78,7 +78,7 @@ public function loadFixtures(array $classNames): void
     protected function loadFixtureClass(Loader $loader, string $className): void
     {
         if (!class_exists($className)) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new \InvalidArgumentException(\sprintf(
                 'Fixture class "%s" does not exist.',
                 $className
             ));
diff --git a/src/Functional/DbManager/PHPCR.php b/src/Functional/DbManager/PHPCR.php
index 4a86fab..6ebb1b8 100644
--- a/src/Functional/DbManager/PHPCR.php
+++ b/src/Functional/DbManager/PHPCR.php
@@ -81,7 +81,7 @@ public function loadFixtureClass(Loader $loader, $class): void
             $fixture = $class;
         } else {
             if (!class_exists($class)) {
-                throw new \InvalidArgumentException(sprintf(
+                throw new \InvalidArgumentException(\sprintf(
                     'Fixture class "%s" does not exist.',
                     $class
                 ));
diff --git a/src/Functional/DbManager/PhpcrDecorator.php b/src/Functional/DbManager/PhpcrDecorator.php
index c1ab08b..12fe07a 100644
--- a/src/Functional/DbManager/PhpcrDecorator.php
+++ b/src/Functional/DbManager/PhpcrDecorator.php
@@ -26,7 +26,7 @@ public function __construct(ContainerInterface $container)
         parent::__construct($container->get('doctrine_phpcr'), $container->get('doctrine_phpcr.initializer_manager'));
     }
 
-    public function getOm(string $managerName = null): DocumentManagerInterface
+    public function getOm(?string $managerName = null): DocumentManagerInterface
     {
         return $this->getDocumentManager($managerName);
     }
diff --git a/src/HttpKernel/TestKernel.php b/src/HttpKernel/TestKernel.php
index 27b7b06..8044b27 100644
--- a/src/HttpKernel/TestKernel.php
+++ b/src/HttpKernel/TestKernel.php
@@ -107,7 +107,7 @@ public function requireBundleSets(array $names): void
     public function requireBundleSet(string $name): void
     {
         if (!isset($this->bundleSets[$name])) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new \InvalidArgumentException(\sprintf(
                 'Bundle set %s has not been registered, available bundle sets: %s',
                 $name,
                 implode(',', array_keys($this->bundleSets))
@@ -116,7 +116,7 @@ public function requireBundleSet(string $name): void
 
         foreach ($this->bundleSets[$name] as $bundle) {
             if (!class_exists($bundle)) {
-                throw new \InvalidArgumentException(sprintf(
+                throw new \InvalidArgumentException(\sprintf(
                     'Bundle class "%s" does not exist.',
                     $bundle
                 ));
@@ -199,7 +199,7 @@ protected function registerConfiguredBundles(): void
         foreach ($bundles as $class => $environments) {
             if (isset($environments['all']) || isset($environments[$this->environment])) {
                 if (!class_exists($class)) {
-                    throw new \InvalidArgumentException(sprintf(
+                    throw new \InvalidArgumentException(\sprintf(
                         'Bundle class "%s" does not exist.',
                         $class
                     ));
diff --git a/src/Unit/Constraint/SchemaAcceptsXml.php b/src/Unit/Constraint/SchemaAcceptsXml.php
index d3913ae..db58842 100644
--- a/src/Unit/Constraint/SchemaAcceptsXml.php
+++ b/src/Unit/Constraint/SchemaAcceptsXml.php
@@ -32,7 +32,7 @@ public function matches($schemaFile): bool
             $configElement = $dom->getElementsByTagName('config');
 
             if (1 !== $configElement->length) {
-                throw new \InvalidArgumentException(sprintf('Can only test a file if it contains 1 <config> element, %d given', $configElement->length));
+                throw new \InvalidArgumentException(\sprintf('Can only test a file if it contains 1 <config> element, %d given', $configElement->length));
             }
 
             $configDom = new \DOMDocument();
@@ -61,7 +61,7 @@ public function toString(): string
 
     protected function failureDescription($schemaFile): string
     {
-        return sprintf(
+        return \sprintf(
             'Xml is accepted by the XML schema "%s"',
             $schemaFile
         );
diff --git a/src/Unit/XmlSchemaTestCase.php b/src/Unit/XmlSchemaTestCase.php
index 1c53e8a..4d723eb 100644
--- a/src/Unit/XmlSchemaTestCase.php
+++ b/src/Unit/XmlSchemaTestCase.php
@@ -46,7 +46,7 @@ private static function getSchemaAcceptsXmlConstraint($xmlDoms)
             }
 
             if (!$dom instanceof \DOMDocument) {
-                throw new \InvalidArgumentException(sprintf('The first argument of assertSchemaAcceptsXml should be instances of \DOMDocument, "%s" given', \get_class($dom)));
+                throw new \InvalidArgumentException(\sprintf('The first argument of assertSchemaAcceptsXml should be instances of \DOMDocument, "%s" given', \get_class($dom)));
             }
 
             return $dom;
diff --git a/tests/Functional/BaseTestCaseTest.php b/tests/Functional/BaseTestCaseTest.php
index dbfaa8c..04ee25c 100644
--- a/tests/Functional/BaseTestCaseTest.php
+++ b/tests/Functional/BaseTestCaseTest.php
@@ -113,7 +113,7 @@ public function testDb(string $dbName, string|null $expected): void
             return;
         }
 
-        $className = sprintf(
+        $className = \sprintf(
             'Symfony\Cmf\Component\Testing\Functional\DbManager\%s',
             $expected
         );