I am currently working through a CCM upgrade from 4.1(2)SR1 -> 4.1(3) for purposes of the DST change. This is a CCM cluster of 2, and it is centralized for a total of 6 offices connected by full T1's.
I have gone through the upgrade documentation, and have no issues with the process. My question is, what is the best practice for handling all of the phones. So, I'll upgrade the Pub first, and the phones will be pointing to the Sub. Then, I'll upgrade the Sub, while the phones are pointing to the Pub. At what point do I actually restart the phones so that they'll get the new software? What's the best way to handle this?