The Symfony php framework is frequently updated. Detecting which version is actively installed, however, is not well documented. Here is how to do it.
As Symfony has continued to progress and evolve, the differences between versions are becoming more and more important. Often I log into an installation and wonder which version is currently on the server.
From the command line / terminal run the following command:
symfony -V
This will return the current version of symfony that is installed on your server.
Happy developing!