diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0d8e0a8..9aea3eb 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -28,6 +28,7 @@ jobs:
         php:
           - "8.2"
           - "8.3"
+          - "8.4"
         symfony:
           - "^6.4"
           - "^7.0"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index af44628..413d38d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+* Added support for PHP 8.4
+
 ## 3.1.0 - 2023-12-17
 
 * Added support for PHP 8.3
diff --git a/composer.json b/composer.json
index d622194..2a6f80f 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
         }
     ],
     "require": {
-        "php": "~8.1.0 || ~8.2.0 || ~8.3.0",
+        "php": "~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
         "ramsey/uuid": "^4.7.5",
         "symfony/serializer": "^6.4 || ^7.0.1"
     },
diff --git a/src/Normalizer/UuidNormalizer.php b/src/Normalizer/UuidNormalizer.php
index 1a40f37..341f3b4 100644
--- a/src/Normalizer/UuidNormalizer.php
+++ b/src/Normalizer/UuidNormalizer.php
@@ -13,7 +13,7 @@ class UuidNormalizer implements NormalizerInterface, DenormalizerInterface
     /**
      * @param array<string, mixed> $context
      */
-    public function denormalize(mixed $data, string $type, string $format = null, array $context = []): UuidInterface
+    public function denormalize(mixed $data, string $type, ?string $format = null, array $context = []): UuidInterface
     {
         if (!is_string($data)) {
             throw NotNormalizableValueException::createForUnexpectedDataType(sprintf('The data is not a valid "%s" string representation.', $type), $data, ['string']);
@@ -24,7 +24,7 @@ public function denormalize(mixed $data, string $type, string $format = null, ar
     /**
      * @param array<string, mixed> $context
      */
-    public function supportsDenormalization(mixed $data, string $type, string $format = null, array $context = []): bool
+    public function supportsDenormalization(mixed $data, string $type, ?string $format = null, array $context = []): bool
     {
         return is_string($data) && is_a($type, UuidInterface::class, true) && Uuid::isValid($data);
     }
@@ -33,7 +33,7 @@ public function supportsDenormalization(mixed $data, string $type, string $forma
      * @param UuidInterface $object
      * @param array<string, mixed> $context
      */
-    public function normalize(mixed $object, string $format = null, array $context = []): string
+    public function normalize(mixed $object, ?string $format = null, array $context = []): string
     {
         return $object->toString();
     }
@@ -41,7 +41,7 @@ public function normalize(mixed $object, string $format = null, array $context =
     /**
      * @param array<string, mixed> $context
      */
-    public function supportsNormalization(mixed $data, string $format = null, array $context = []): bool
+    public function supportsNormalization(mixed $data, ?string $format = null, array $context = []): bool
     {
         return $data instanceof UuidInterface;
     }