Symfony 5.3.1 has just been released. Here is a list of the most
important changes:

bug #41463 [Serializer][Validator] Fix not null return from “getCollectionValueTypes” (@jderusse)
bug #41493 [Security] Readd deprecated methods to the interfaces (@wouterj)
bug #41495 [HttpFoundation] Add ReturnTypeWillChange to SessionHandlers (@nikic)
bug #41485 [HttpKernel] fix ArgumentMetadataFactory messes up controller arguments with attributes (@sgehrig)
bug #41461 Fix Symfony 5.3 end of maintenance date (@jmsche)

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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version is not maintained anymore? Or only when a security issue is fixed?
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