Little over a month after Apple reportedly contacted developers advising them to step up the depreciation of UDIDs, the firm has started outright rejecting any new titles that utilise the ID standard.

That's according to a story on TechCrunch, which claims several Playhaven clients had seen their apps rejected by Apple, with their use of UDIDs the only common denominator.

To ID or not to UDID

UDIDs are used by analytics firms and ad networks to track user activity from one app to the next, providing insightful data for developers so they can tweak their titles to encourage user retention.

Some have claimed the technique represents a security risk, however, and under what's believed to be increasing scrutiny from US Congress regarding user privacy, it's suggested Apple has picked up the pace of its UDID phase out.

TechCrunch claims two of Apple's 10 review teams started blanket rejections of apps that access UDIDs this week.

Next week, two more teams will start rejecting apps in the same way, until all 10 teams are on board within a further three weeks.

The race is now on, therefore, for third parties to devise an alternative that doesn't raise the same privacy concerns at Apple, with W3i have previously proposed the now discounted option of using the MAC address of the iOS device's Wi-Fi network interface as a replacement.

[source: TechCrunch]