iOS 11.4 - Update Novelties

[toucana]

Just in case anyone else trips over these:

i. Apple now appears to be enforcing Two Factor Authentication when using an Apple ID across multiple devices. (it was previously optional).

ii. Touch ID may be deactivated and your pre-existing fingerprint files may be wiped - This can happen if you had a debit/credit card listed as the payment method on your Apple Account, and the expiry date of the card has passed. This seems to be because Touch ID can be used as a verification method for authorising payments on an Apple Store account. If you update iOS and Apple finds an expired card on your account, it disables Touch ID, wipes your fingerprint files, and greys out the 'Add Fingerprint' option as well. You have to update the payment method on your account to regain Touch ID functionality, and then scan a new fingerprint to set up Touch ID from scratch again- (you do remember your passcode don't you ?)

Number ii. is particularly annoying because at first glance it appears to match the symptoms of a hardware failure in the capacitative sensor in the finger print scanner system. There is very little explanatory documentation readily available from Apple on the practical details of these latest security improvements in iOS 11.4.