I'm going to be going through a significant call manager upgrade, although my user base is small (less than 100 phones).
Here is my problem, I don't have a test environment, so I'll be doing a lot of work on the weekends. The upgrade includes a whole new server and this is where my question comes in. If I start installing and shutdown my old call manager while bringing the new box up, can I simply shutdown the old one in a worst case senario and failback to my old box? Will phones downgrade software when the old CM comes up if the new box had pushed out new software to the phones?