I am upgrading to version 12 tomorrow. I would like to keep the phone system running during the upgrade. I have the option to install v12 on a temp server - changing the IP address to the known 3CX IP so that the phones will still connect. I will then prepare the existing 3CX server with V12. When it's ready I will switch back to the original server. First off, will this work? Secondly, can I move the license from one server back to the other?