Monkeypeew wrote:
I know if you have the iPhone app and you have an update for it you need to take the athenticator off your account before you update then reattach it
I've never had any problems with software updates to the authenticator app or iOS updates (and I have 2 battle.net accounts, one linked to an iPhone, and one to an iPad). But, before I ever do an iOS update, I back them up and then restore them after the update (I know syncing before and after the update should take care of everything for you, but it doesn't touch app data/settings). To do it, plug in your device and let it sync. Then rightclick on it in iTunes and select backup. After doing the iOS update, let it sync again, then rightclick on it again and select restore from backup.
I started doing this because of loosing my app settings and saved games (my bank role for a single player holdem game mainly) after iOS updates. It was after this that I switched to the mobile authenticator. The only time I have removed it from my account was when I upgraded phones and wanted to switch it to the new one.