How do I Update server version in 7 days to die

How do I update an existing 7 days to die server to a newer version? I have a server running 7 days 20.3(B3) and now that 20.4 is out i have a player having issues because his game version is incompatible. Corollary, how do I tell the system to use an older version if I wanted to have it run something other than the latest when I start the setup?

shut it down / stop server and hit update before you start it again

ok, that much works, now… how do I tell it to NOT upgrade and load 20.3 instead of 4 when I start a new server up?
What I did to “fix” it… stop the instance, connect to the windows box running the server, go in to the C:\AMPDatastore\Instances\Placeholder\7d2d\ folder (placeholder will be whatever you named the instance) and run steam CMD. change the install path to C:\AMPDatastore\Instances\Placeholder\7d2d\294420, login anonymously, and run app_update 299320 -beta alpha20.3
this downgraded my 20.4 to 20.3.