You are browsing the Symfony 4 documentation, which changes significantly from Symfony 3.x. If your app doesn't use Symfony 4 yet, browse the Symfony 3.4 documentation.
Contributing to Symfony
This part of the documentation tells you everything you want to know about how you can be involved with the Symfony project; from contributing documentation to fix bugs.
4.1 version
Maintained
Unmaintained
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