With the iOS 14.2 upgrade, there was an additional push from Apple to get me to upgrade my Apple ID to two-factor authentication–but I’m not sure how feasible this is. The problem stems from my use of multiple Apple IDs.
(1) Long ago, I established an Apple ID of (something)@mac.com. This was originally established as a free trial iTools or .Mac account, and I never shifted over to the paid service. I started using this account for iTunes store purchases, and it is the account used for all my music, video, and iOS app purchases.
(2) Much later, I got an Apple ID of (myname)@me.com under MobileMe. This has been my primary iCloud login since iCloud started; it handles my contacts and calendar, and is the primary Apple ID associated with my iOS devices and on my iMac. When the Mac OS App Store showed up, I made sure that I started using this account for Mac OS app purchases. (When there is a choice, I still purchase the non-App Store versions of an application when I can, but I have built up a number of App Store apps over the years.)
When two-factor authentication was first introduced, I enabled it for my newer primary account. My understanding at the time was that for a device to be available for authentication for an Apple ID, that Apple ID had to be the single primary Apple ID for the device.
Now I’m getting asked by the device to add two-factor authentication to the older account as well–but I’m not sure if this is practical. Neither of my iOS devices is going to have the @mac.com address as their primary associated iCloud account. I can probably create a secondary user login on my iMac, and have that account use the @mac.com address as its associated iCloud account, but I think that would mean that there would be situations where authenticating to that account on an iOS device would require physical access to my iMac. That’s straightforward in pandemic times, but once I start actually leaving the house I could see it causing problems.
Is it possible to have Apple’s two-factor authentication set up so that an iOS device can be used as the second factor for an Apple ID other than the primary iCloud account? Or is there no practical way for me to add 2FA to my older “store-only” account?