iOS 7 Eliminates MAC Address As Tracking Option, Signaling Final Push Towards Apple’s Own Ad Identifier Technology

Apple has now taken another step to push app publishers to use its preferred ad tracking option, the Identifier for Advertisers (IDFA), with the debut of the iOS 7 beta. Confirming what many have suspected, Apple is eliminating an alternative option involving tracking by MAC addresses. This method had sprung up following a change to Apple’s Developer Documentation in 2011, announcing its intention to end developers’ reliance on the unique identifier known as the UDID.

It’s been a long time since Apple announced it would begin phasing out developer access to the UDID on iOS devices like the iPhone and iPad – something which at first led to some confusion in the industry. Over the years, developers had learned to use the identifier for advertising purposes, and as a way to store data about their users. But the method raised privacy concerns, since the number is tied to each individual device and cannot be removed, cleared, or controlled by end users.

Several alternatives soon appeared in the UDID’s place, each hoping to become the new default method. Many developers still use some these – or just as likely, a combination of some these – today.

Earlier this year, Apple began signaling again that the alternative it had in mind for the post-UDID world was its own when it began rejecting apps using cookie-tracking methods. Then in March, the company announced that it would no longer accept new applications or app updates that access UDIDs as of May 1, 2013.


With that deadline now behind us, Apple is again pushing its community to the UDID’s more privacy conscious replacement, the IDFA. This Apple-approved method provides the attribution advertisers need, along with the privacy and security controls Apple wants to provide for its users.

According to data collected by mobile app marketing firm Fiksu, which helps app publishers with user acquisition efforts, iOS 7 devices – all beta testers, at this point – are always now returning a MAC address of 02:00:00:00:00:00. This “dummy” address is the equivalent of the phone number 555-1212, for example. It began showing up for the tens of thousands of unique iOS 7 devices in Fiksu’s logs earlier this week, says Craig Palli, Fiksu’s mobile app marketing technology platform head.

There is also a mention in the pre-release notes for iOS 7 distributed to developers which states that this single, meaningless MAC address is now the new expected behavior.

“The MAC address, a hardware based identifier, has long been a way for advertisers to have a permanent, unique identifier for each device, providing a stable tracking option as an alternative to the controversy-plagued UDID,” Palli explains. “However, the same privacy concerns raised about the UDID apply equally to the MAC address – it just received less publicity,” he adds. Now, for those who haven’t yet made the switch to IDFA, the window to migrate is closing.

That being said, Palli says that most publishers and ad networks generally knew that the MAC method would not be supported, and the amount of traffic addressed by MAC addresses had “rapidly diminished” in recent months. Today, it exists as a very small, single-digit percentage, he tells us. Other methods, including digital fingerprinting and to a lesser extent, HTML5 cookies, are also still in use today, both with their own strengths and weaknesses.

At this time, there have not yet been any reports of app rejections because of the MAC address method being used, though, as noted above, the cookie-tracking method had seen some rejections earlier this year.

The app publisher and advertiser communities have had a long time to prepare for UDID’s demise and the shift to the IDFA. And while that hasn’t been an entirely error-free process, the time has now come to finalize the move.

“Fortunately, as an ecosystem, we’ve transitioned to the IDFA,” says Palli, “so by the time iOS 7 rolls out it should make little to no difference from an app developer or marketer’s point of view.”