IDFV would be perfect. Just need to be aware of one caveat, if the user deletes all apps from a developer (or is on another device) and reinstalls an app, the

IDFV would be perfect. Just need to be aware of one caveat, if the user deletes all apps from a developer (or is on another device) and reinstalls an app, the IDFV will be different. Seems like they could come up with a solution that hashes some company and user attributes to provide a consistent ID across all of a single developers apps.