diff --git a/UPGRADE-6.3.md b/UPGRADE-6.3.md
index f3245d6a9bbd..3c6ffb56aa37 100644
--- a/UPGRADE-6.3.md
+++ b/UPGRADE-6.3.md
@@ -112,3 +112,4 @@ Serializer
 
  * Deprecate `MissingConstructorArgumentsException` in favor of `MissingConstructorArgumentException`
  * Deprecate `CacheableSupportsMethodInterface` in favor of the new `getSupportedTypes(?string $format)` methods
+ * The following Normalizer classes will become final in 7.0: `ObjectNormalizer`
diff --git a/src/Symfony/Component/Serializer/CHANGELOG.md b/src/Symfony/Component/Serializer/CHANGELOG.md
index 6b897c1eae96..ba277a3870b3 100644
--- a/src/Symfony/Component/Serializer/CHANGELOG.md
+++ b/src/Symfony/Component/Serializer/CHANGELOG.md
@@ -10,6 +10,7 @@ CHANGELOG
  * Make `ProblemNormalizer` give details about `ValidationFailedException` and `PartialDenormalizationException`
  * Deprecate `MissingConstructorArgumentsException` in favor of `MissingConstructorArgumentException`
  * Deprecate `CacheableSupportsMethodInterface` in favor of the new `getSupportedTypes(?string $format)` methods
+ * The following Normalizer classes will become final in 7.0: `ObjectNormalizer`
 
 6.2
 ---
diff --git a/src/Symfony/Component/Serializer/Normalizer/ObjectNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/ObjectNormalizer.php
index dc5067dfb6f4..f4e50841e9c2 100644
--- a/src/Symfony/Component/Serializer/Normalizer/ObjectNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/ObjectNormalizer.php
@@ -25,6 +25,8 @@
  * Converts between objects and arrays using the PropertyAccess component.
  *
  * @author Kévin Dunglas <dunglas@gmail.com>
+ *
+ * @final since Symfony 6.3
  */
 class ObjectNormalizer extends AbstractObjectNormalizer
 {