I just chatted with an Apple support person. They said that the 5S and the 6's use the same type SIM card. When my new phone arrives I just pop SIM card out that came with it and pop in the one in my current phone with is already coded with my current unlimited service which should be uninterrupted. They said I can do it myself at home. That way an ATT associate who's goal is to not have me keep my unlimited plan won't be able to interfere with the process!
I'm counting on it.
Sent from my iPhone
I'm counting on it.
Sent from my iPhone