Hi everyone, we've received an increased number of requests from players to have us help them reset/replace the mobile authenticator on the account - this is likely due to the OS on many mobile devices recently being updated. Some helpful advice for those of you who use the app:
1) Before updating the OS on your device, you can go through Battle.net and then remove the authenticator yourself, then after the update, put it back on. (This is what I do). More information about removing and replacing the app in the account can be found here.
2) You can copy down the serial and restore code in the authenticator before you run the update - Menu > Setup > Continue (there you'll see both the serial and the restore codes). If after the update you get a couple of 'authenticator invalid' responses, go back into the authenticator, only instead of hitting Setup, choose Restore > follow the next prompt, and enter in the appropriate (original codes).
Of note: there's also SMS Protect which will help you get into the account even if you have issues with the authenticator.
Our Support Channel on YouTube also features a video about adding and removing the authenticators.
Hope that helps! If you have any questions about that please let me know.
Cheers,
Araxom
Blizzard Customer Support
P.S. If you have a moment, please let us know if this information was helpful to you. Thanks!