Symfony 6.3.12 has just been released.
Here is the list of the most important changes since 6.3.11:

bug #52913 [Routing] Fixed priority getting lost when setting localized prefix (@pritasil)
bug #53183 [Messenger] PhpSerializer: TypeError should throw MessageDecodingFailedException (@B-Galati)
bug #52131 [HttpKernel] Fix RequestPayloadValueResolver handling error with no ExpectedTypes (@Jeroeny)
bug #51559 [DependencyInjection] #[Autowire] attribute should have precedence over bindings (@HypeMC)
bug #53678 [Mime] Fix serializing uninitialized RawMessage::$message to null (@nicolas-grekas)
bug #53634 [Notifer][Smsapi] Set messageId of SentMessage (@tomasz-kusy)
bug #53501 [DependencyInjection] support lazy evaluated exception messages with Xdebug 3 (@xabbuh)
bug #52994 [MonologBridge] Fix context data and display extra data (@louismariegaborit)
bug #53671 [HttpClient] Fix pausing responses before they start when using curl (@nicolas-grekas)
bug #53663 [TwigBridge] separate child and parent context in NotificationEmail on writes (@xabbuh)
bug #53667 [Mailer] [Mailgun] Fix sender header encoding (@spajxo)
bug #53157 [Mailer] Throw TransportException when unable to read from socket (@xdanik)
bug #53361 [Serializer] Take unnamed variadic parameters into account when denormalizing (@thijsBreker)
bug #53530 [Serializer] Rewrite AbstractObjectNormalizer::createChildContext() to use the provided cache_key from original context when creating child contexts (@amne)
bug #53506 [HttpClient] Fix error chunk creation in passthru (@rmikalkenas)
bug #53260 [AssetMapper] Handle assets with non-ascii characters in dev server (@fbourigault)
bug #53357 [Translation] Fix TranslationNodeVisitor with constant domain (@VincentLanglet)
bug #53525 [Messenger] [AMQP] Throw exception on nack callback (@kvrushifa)
bug #53432 [HttpFoundation] Request without content-type or content-length header should result in null values, not empty strings (@priyadi)
bug #53593 [Cache] Fix possible infinite loop in CachePoolPass (@HypeMC)
bug #53588 [Translation] fix multi-byte code area to convert (@xabbuh)
bug #53572 [FrameworkBundle] grab a service from the container only if it exists (@xabbuh)
bug #53565 [Mime] Fix undefined array key 0 when empty sender (@0x346e3730)
bug #53516 [Console] Allow ‚0‘ as a $shortcut in InputOption.php (@lawsonjl-ornl)
bug #53576 [Console] Only execute additional checks for color support if the output (@theofidry)
bug #53582 [TwigBundle] Fix configuration when „paths“ is null (@smnandre)
bug #53575 [Mailer] register the MailPaceTransportFactory (@xabbuh)
bug #53581 [String] fix aircraft inflection (@renanbr)
bug #53509 [Security] Fix AuthenticationUtils::getLastUsername() returning null (@alexandre-daubois)
bug #53567 [String] Correct inflection of axis (Vladislav Iurciuc)
bug #53537 [VarDumper] Fix missing colors initialization in CliDumper (@nicolas-grekas)
bug #53481 [Process] Fix executable finder when the command starts with a dash (@kayw-geek)
bug #53006 [ErrorHandler] Don’t format binary strings (@aleho)
bug #53453 [Translation] add support for nikic/php-parser 5.0 (@xabbuh)
bug #53441 [Messenger] Amazon SQS Delay has a max of 15 minutes (@alamirault)
bug #53383 [Validator] re-allow an empty list of fields (@xabbuh)
bug #53418 [FrameworkBundle][Notifier] Fix service registration (MessageBird + TurboSms) (@smnandre)
bug #53350 [Validator] fix the exception being thrown (@xabbuh)
bug #53341 [FrameworkBundle] append instead of replacing potentially non-existent named-arguments (@xabbuh)
bug #53320 [Cache][DependencyInjection][Lock][Mailer][Messenger][Notifier][Translation] Url decode username and passwords from parse_url() results (@alexandre-daubois)
bug #53108 [Serializer] Fix using deserialization path 5.4 (@HypeMC)

WARNING: 6.3.12 is the last version for the Symfony 6.3 branch. If some
of your projects are still using this version, consider upgrading as soon as possible.

Want to upgrade to this new release? Because Symfony protects
backwards-compatibility very closely, this should be quite easy. Use
SymfonyInsight upgrade reports
to detect the code you will need to change in your project and
read our upgrade
documentation to learn more.

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