How to specfiy minecrat Java version?

[Elekam]

Hey, I would like to downgrade my 1.20.4 server to 1.20.1. I see a versions folder in /serverfiles/ and found this documentation.

It says I can specify the version, but doesn't elaborate how. I cant find it anywhere. Ig I might be able to replace the minecraft_server.jar with a 1.20.1 before install but is that the right way?

Edit: I found the "mcversion" variable in the _default.cfg of lgsm-config. I added this variable to the mcserver.cfg and reinstalled the server. But the version is still 1.20.4. Does it ignore the variable, does it not use the mcserver.cfg?