I am currently running CUCM 8.5.1 and I need to install a CUCM Device Pack to enable support for the 8831 conference phone.
Will my current "default" firmware loads be changed after the device pack is installed?
I know that when you install a specific device firmware the default load changes to what was just installed, and you need to change it back if you want to do testing before all devices in your cluster update to the "new" default.
Normally when installing device packs the default firmware for the endpoints will change to the latest release in regards to when the device pack was made available. You are also correct in stating that you can simply copy the current firmware version--install the device pack--and then revert your device defaults back to the copied versions in order to not affect your production environment.
I had a feeling that would be the case, I was unsure if CM device packs would have different rules than Device specific device packs. I haven't have had to apply a CM device pack to our cluster until now!