[note: this is technical post for iOS developers, publishers and ad networks]

Do you remember all the fuss about UDID? Yup, the dust has settled on this one, like most things. But today is the right day to revive the topic!

UDID tracking posed a number of ethical and user privacy concerns a few years back, yet it was the most efficient way for advertisers to track the efficiency of their campaigns. This short blog post will briefly cover the past, the present and the future of such identifiers, especially as applied to advertising tracking.

In a few days, many of us are expecting the formal announcement of iOS 7 at the WWDC keynote. Whether or not iOS 7 is announced, the reality is that iOS 6 adoption has by now eclipsed previous […]Read more


OpenUDID adoption has accelerated in the past few weeks and seems to have reached a sort of critical mass. In fact, a study by Fiksu shows OpenUDID as the most widely adopted “universal” alternatives (i.e. one that does not presupposed prior agreement between parties).

The picture featured on the OpenUDID GitHub (below) shows a variety of known industry players that have adopted the initiative: analytics companies, advertising networks, authority bodies as well as other value-adding SDK publishers. Others are in the process of integrating OpenUDID.

This is good news for the industry because it means that some sort of “common” ground and exchange token can be used to resume business as usual. But not only: OpenUDID is putting the user back in […]Read more


Lame and inelegant. This was our reaction when we discovered that a launch partner of OpenUDID, Crashlytics, decided to create an alternative to the UDID called SecureUDID. It’s not so much about the code and the product, but rather the process and the lack of disclosure. The issue here is really about Open Source project netiquette.

Back to the origins

When Apple announced the deprecation of the UDID almost a year ago, we were amongst the first to set time aside and start building an alternative. We wanted it to be open source and Appsfire would support it.

It was announced publicly and it instantly attracted the interest of hundreds of developers, including some nice brand names. Crashlytics was one of them – they wanted to contribute and also be part of the launch operation PR. We announced […]Read more


We’ve covered this issue before, preemptively. But now is the time to act!

Some reports have emerged that Apple is now massively rejecting apps that still use the “[UIDevice uniqueIdentifier]” a.k.a. the UDID (Unique Device IDentifier). This means that developers have two choices: drop using this entirely, or find a replacement.

Some have gone the MAC address way, which we strongly advocate against because it is an even more sensitive unique identifier typically used to authenticate devices on VPNs and other private WLANs. So it too faces the risk to be deprecated. And rightly so!

So, if you haven’t done so already, go and check the open-source drop-in replacement, an effort we participate in:


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With the introduction of iOS 5, Apple implicitly indicated that it will soon remove the ability for developers to access the unique device identifier, also known as UDID. While not the most important API in the entire iOS SDK, many in the app ecosystem have grown dependent on this UDID, for legitimate aggregate measurement needs, not for individual tracking purposes. The problem is real and yet both sides of the solution (!) have legitimate claims. A recent article on TechCrunch articulates the mobile conundrum very well.

In anticipation of this imminent restriction (which in some cases already appears to be enforced as alluded to here or here), a number of actors have adopted a substitute open-source approach that Appsfire helped bootstrap: […]Read more