diff --git a/Serializer/ConstraintViolationListNormalizer.php b/Serializer/ConstraintViolationListNormalizer.php
index c20fedf..ce0c728 100644
--- a/Serializer/ConstraintViolationListNormalizer.php
+++ b/Serializer/ConstraintViolationListNormalizer.php
@@ -14,7 +14,6 @@
 namespace ApiPlatform\JsonApi\Serializer;
 
 use ApiPlatform\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
 use Symfony\Component\Serializer\NameConverter\NameConverterInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\TypeInfo\Type\ObjectType;
@@ -94,15 +93,8 @@ private function getSourcePointerFromViolation(ConstraintViolationInterface $vio
             $fieldName = $this->nameConverter->normalize($fieldName, $class, self::FORMAT);
         }
 
-        if (!method_exists(PropertyInfoExtractor::class, 'getType')) {
-            $type = $propertyMetadata->getBuiltinTypes()[0] ?? null;
-            if ($type && null !== $type->getClassName()) {
-                return "data/relationships/$fieldName";
-            }
-        } else {
-            if ($propertyMetadata->getNativeType()?->isSatisfiedBy(static fn ($t) => $t instanceof ObjectType)) {
-                return "data/relationships/$fieldName";
-            }
+        if ($propertyMetadata->getNativeType()?->isSatisfiedBy(static fn ($t) => $t instanceof ObjectType)) {
+            return "data/relationships/$fieldName";
         }
 
         return "data/attributes/$fieldName";
diff --git a/Serializer/ErrorNormalizer.php b/Serializer/ErrorNormalizer.php
index 3b6d2fb..2076a1c 100644
--- a/Serializer/ErrorNormalizer.php
+++ b/Serializer/ErrorNormalizer.php
@@ -45,10 +45,9 @@ public function normalize(mixed $data, ?string $format = null, array $context =
             $error['code'] = $data->getId();
         }
 
-        // TODO: change this 5.x
-        // if (isset($error['status'])) {
-        //     $error['status'] = (string) $error['status'];
-        // }
+        if (isset($error['status'])) {
+            $error['status'] = (string) $error['status'];
+        }
 
         if (!isset($error['violations'])) {
             return ['errors' => [$error]];
diff --git a/Tests/JsonSchema/ReservedAttributeNameSchemaFactoryTest.php b/Tests/JsonSchema/ReservedAttributeNameSchemaFactoryTest.php
index 0b0d46b..a1865ab 100644
--- a/Tests/JsonSchema/ReservedAttributeNameSchemaFactoryTest.php
+++ b/Tests/JsonSchema/ReservedAttributeNameSchemaFactoryTest.php
@@ -62,7 +62,7 @@ protected function setUp(): void
             );
         }
 
-        $definitionNameFactory = new DefinitionNameFactory(null);
+        $definitionNameFactory = new DefinitionNameFactory();
 
         $baseSchemaFactory = new BaseSchemaFactory(
             resourceMetadataFactory: $resourceMetadataFactory->reveal(),
diff --git a/Tests/JsonSchema/SchemaFactoryTest.php b/Tests/JsonSchema/SchemaFactoryTest.php
index 648cfd8..2c11df8 100644
--- a/Tests/JsonSchema/SchemaFactoryTest.php
+++ b/Tests/JsonSchema/SchemaFactoryTest.php
@@ -59,7 +59,7 @@ protected function setUp(): void
         $propertyNameCollectionFactory->create(Dummy::class, ['enable_getter_setter_extraction' => true, 'schema_type' => Schema::TYPE_INPUT])->willReturn(new PropertyNameCollection());
         $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
 
-        $definitionNameFactory = new DefinitionNameFactory(null);
+        $definitionNameFactory = new DefinitionNameFactory();
 
         $baseSchemaFactory = new BaseSchemaFactory(
             resourceMetadataFactory: $resourceMetadataFactory->reveal(),
@@ -316,7 +316,7 @@ private function buildSchemaFactoryWithPolymorphicRelation(): SchemaFactory
         $resourceClassResolver->isResourceClass(RelatedDummy::class)->willReturn(true);
         $resourceClassResolver->isResourceClass(OtherRelatedDummy::class)->willReturn(true);
 
-        $definitionNameFactory = new DefinitionNameFactory(null);
+        $definitionNameFactory = new DefinitionNameFactory();
 
         $baseSchemaFactory = new BaseSchemaFactory(
             resourceMetadataFactory: $resourceMetadataFactory->reveal(),
@@ -377,7 +377,7 @@ private function buildSchemaFactoryWithRelation(): SchemaFactory
         $resourceClassResolver->isResourceClass(Dummy::class)->willReturn(true);
         $resourceClassResolver->isResourceClass(RelatedDummy::class)->willReturn(true);
 
-        $definitionNameFactory = new DefinitionNameFactory(null);
+        $definitionNameFactory = new DefinitionNameFactory();
 
         $baseSchemaFactory = new BaseSchemaFactory(
             resourceMetadataFactory: $resourceMetadataFactory->reveal(),
diff --git a/Util/ResourceLinkageResolver.php b/Util/ResourceLinkageResolver.php
index 73cacb9..9c47573 100644
--- a/Util/ResourceLinkageResolver.php
+++ b/Util/ResourceLinkageResolver.php
@@ -16,7 +16,6 @@
 use ApiPlatform\Metadata\ApiProperty;
 use ApiPlatform\Metadata\ResourceClassResolverInterface;
 use ApiPlatform\Metadata\Util\TypeHelper;
-use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
 use Symfony\Component\TypeInfo\Type;
 use Symfony\Component\TypeInfo\Type\CompositeTypeInterface;
 use Symfony\Component\TypeInfo\Type\ObjectType;
@@ -48,25 +47,6 @@ public function getRelationships(ApiProperty $propertyMetadata): array
     {
         $relationships = [];
 
-        if (!method_exists(PropertyInfoExtractor::class, 'getType')) {
-            foreach ($propertyMetadata->getBuiltinTypes() ?? [] as $type) {
-                if ($type->isCollection()) {
-                    $collectionValueType = $type->getCollectionValueTypes()[0] ?? null;
-                    if ($collectionValueType && ($className = $collectionValueType->getClassName()) && $this->resourceClassResolver->isResourceClass($className)) {
-                        $relationships[] = [$className, true];
-                    }
-
-                    continue;
-                }
-
-                if (($className = $type->getClassName()) && $this->resourceClassResolver->isResourceClass($className)) {
-                    $relationships[] = [$className, false];
-                }
-            }
-
-            return $relationships;
-        }
-
         if (null === $type = $propertyMetadata->getNativeType()) {
             return $relationships;
         }
diff --git a/composer.json b/composer.json
index 4b61971..c0226c9 100644
--- a/composer.json
+++ b/composer.json
@@ -22,11 +22,11 @@
     ],
     "require": {
         "php": ">=8.2",
-        "api-platform/documentation": "^4.4@alpha",
-        "api-platform/json-schema": "^4.4@alpha",
-        "api-platform/metadata": "^4.4@alpha",
-        "api-platform/serializer": "^4.4@alpha",
-        "api-platform/state": "^4.4@alpha",
+        "api-platform/documentation": "^5.0@alpha",
+        "api-platform/json-schema": "^5.0@alpha",
+        "api-platform/metadata": "^5.0@alpha",
+        "api-platform/serializer": "^5.0@alpha",
+        "api-platform/state": "^5.0@alpha",
         "symfony/error-handler": "^6.4 || ^7.0 || ^8.0",
         "symfony/http-foundation": "^6.4.14 || ^7.0 || ^8.0",
         "symfony/type-info": "^7.3 || ^8.0"
@@ -57,7 +57,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-main": "4.4.x-dev",
+            "dev-main": "5.0.x-dev",
             "dev-4.2": "4.2.x-dev",
             "dev-3.4": "3.4.x-dev",
             "dev-4.1": "4.1.x-dev"