Some iOS app developers are reporting that Apple has begun rejecting apps that access a device's unique identifier (UDID) — a move that was previously suggested when Apple deprecated the UDID in iOS 5 back in August of last year, and now appears to be officially taking effect during a time of increased scrutiny over the company's privacy safeguards. UDIDs are used by some app developers to track user behavior, but their use has been scrutinized since they are permanent and because users are unable to block sending UDIDs to third parties. TechCrunch reports that two of Apple's review teams started "blanket rejections of apps that use UDIDs" this week, and that next week four teams will issue rejections — until all ten review teams reject apps that are using UDIDs.

Since the move away from UDID access has been in the works for some time, iPhone and iPad users don't need to panic about all of their favorite apps being yanked out of the App Store. But developers that continue to use UDIDs may now be feeling the heat to find an alternative.