diff --git a/Cache/CacheWarmer.php b/Cache/CacheWarmer.php
index 372e7a90..c37fdcc9 100644
--- a/Cache/CacheWarmer.php
+++ b/Cache/CacheWarmer.php
@@ -38,7 +38,7 @@ public function __construct(array $includePaths, MetadataFactoryInterface $metad
      *
      * @return string[] A list of classes or files to preload on PHP 7.4+
      */
-    public function warmUp($cacheDir)
+    public function warmUp(string $cacheDir): array
     {
         $finder = Finder::create()
             ->ignoreVCS(true)
diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 173129a9..b3c896c6 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -25,10 +25,7 @@ public function __construct($debug = false)
         $this->debug = $debug;
     }
 
-    /**
-     * @return TreeBuilder
-     */
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         $tb = new TreeBuilder('jms_serializer');
 
diff --git a/ExpressionLanguage/BasicSerializerFunctionsProvider.php b/ExpressionLanguage/BasicSerializerFunctionsProvider.php
index eff59a5f..9b58ebf9 100644
--- a/ExpressionLanguage/BasicSerializerFunctionsProvider.php
+++ b/ExpressionLanguage/BasicSerializerFunctionsProvider.php
@@ -12,7 +12,7 @@ class BasicSerializerFunctionsProvider implements ExpressionFunctionProviderInte
     /**
      * @return ExpressionFunction[]
      */
-    public function getFunctions()
+    public function getFunctions(): array
     {
         return [
             new ExpressionFunction('service', static function ($arg) {
diff --git a/Tests/DependencyInjection/JMSSerializerExtensionTest.php b/Tests/DependencyInjection/JMSSerializerExtensionTest.php
index 9631c1b9..f96fcd59 100644
--- a/Tests/DependencyInjection/JMSSerializerExtensionTest.php
+++ b/Tests/DependencyInjection/JMSSerializerExtensionTest.php
@@ -32,7 +32,7 @@
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
-use Twig\Loader\ContainerRuntimeLoader;
+use Twig\RuntimeLoader\ContainerRuntimeLoader;
 
 class JMSSerializerExtensionTest extends TestCase
 {
diff --git a/composer.json b/composer.json
index 39a848ba..95542183 100644
--- a/composer.json
+++ b/composer.json
@@ -24,26 +24,26 @@
         "php": "^7.2 || ^8.0",
         "jms/serializer": "^3.28",
         "jms/metadata": "^2.6",
-        "symfony/dependency-injection": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/framework-bundle": "^3.4 || ^4.0 || ^5.0 || ^6.0"
+        "symfony/dependency-injection": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/framework-bundle": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0"
     },
     "require-dev": {
         "doctrine/coding-standard": "^8.1",
         "doctrine/orm": "^2.4",
         "phpunit/phpunit": "^8.0 || ^9.0",
-        "symfony/expression-language": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/finder": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/form": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/stopwatch": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/templating": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/twig-bundle": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/uid": "^5.1 || ^6.0",
-        "symfony/validator": "^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/yaml": "^3.4 || ^4.0 || ^5.0 || ^6.0"
+        "symfony/expression-language": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/finder": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/form": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/stopwatch": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/templating": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/twig-bundle": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/uid": "^5.1 || ^6.0 || ^7.0",
+        "symfony/validator": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/yaml": "^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0"
     },
     "suggest": {
-        "symfony/expression-language": "Required for opcache preloading ^3.4 || ^4.0 || ^5.0 || ^6.0",
-        "symfony/finder": "Required for cache warmup, supported versions ^3.4 || ^4.0 || ^5.0 || ^6.0"
+        "symfony/expression-language": "Required for opcache preloading ^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
+        "symfony/finder": "Required for cache warmup, supported versions ^3.4 || ^4.0 || ^5.0 || ^6.0 || ^7.0"
     },
     "config": {
         "allow-plugins": {