Under what conditions is Apple's 'advertisingIdentifier' reset?

Question

Other than the user manually resetting it, has anyone observed other things that will cause the ADID to be reset? OTA OS Upgrades? iTunes Restores?

Answer 1

There is no official, definitive list from Apple. The documentation only states:

This identifier may change—for example, if the user erases the device—so you should not cache it.

Apple don't give any further detail. It's known that resetting the device changes the ADID, as does the user manually resetting it themselves (where this feature is available, so iOS 6.1+). I've not been able to find anything that suggests an OS update would reset the identifier.

It is of course possible other, undocumented behaviour resets the identifier, but I've not been able to find anything else.