The IDFA is Dead

By Peter Farago, Vice President of Flurry

It’s been about a year since Apple dropped the bombshell that it would deprecate its Identifier for Advertisers (IDFA), aiming to bolster consumer privacy. At the same time, this also severely hamstrings how mobile app developers monetize through advertising. The net result of this has been deep-felt industry grief, and we’re still working through the various stages.

First, there was denial. The early chatter was whether Apple was really committed to this. When the company delayed the rollout of their new policy from late 2020 to Spring of 2021, many hoped Apple would ultimately reverse direction. When Apple stayed the course, the conversation quickly shifted to salvaging as much IDFA footprint as possible by maximizing opt-in rates. Some app developers and other companies continue to cite that early opt-in numbers may indicate some glimmer of promise. Unfortunately our data shows the opposite, and more is shared later in this post.

Many in the industry also entered the bargaining stage of grief: Maybe instead of IDFA, we can use fingerprinting? Apple has made it increasingly clear that this isn’t an option. Blocking the use of IP addresses in iOS 14.6 and rejecting some apps that collect IP addresses have started sobering up the ecosystem.

Calling the Time of Death

Rather than continuing to cling tenaciously to a model that depends on individual-level identifiers, it’s time to accept this is no longer possible and move forward. We need to face the fact that the rosiest interpretation of opt-in numbers is both inaccurate and irrelevant. Since Flurry has detected that over 80% of all iOS devices are now upgraded to iOS 14.5 or later, the data is in. And with that, I am calling the IDFA time of death as August 2021.

Data Shows the Flatline

Since the April release of iOS 14.5, the mobile app industry has attempted to read scant tea leaves to predict what things will look like once all Apple users are exposed to App Tracking Transparency (ATT). Some in the industry reported pockets of opt-in numbers as high as 40%.1 However, Flurry’s broad data set doesn’t support that percentage. Based on aggregated insights from 2 billion mobile devices, Flurry is measuring a worldwide opt-in rate of 25% and a U.S. rate of 17% among only those users who have been exposed to the ATT opt-in prompt.2

When we expand beyond just those devices that received a prompt -- looking at the entire device base -- only 13% are opted in. Here’s how it breaks down:3

  • 3% cannot be asked to be tracked (“restricted” status)4
  • 48% have not yet been prompted by apps, putting them into a default not-tracked status5
  • 40% have denied tracking via the prompt or the iOS privacy settings6

Even if the remaining 48% of users, who haven’t yet been prompted, are asked to accept tracking, it would bring the 9% of all iOS 14+ users who can be tracked up to just 21%.7 That final tally would still be too small to support robust user-level targeting and attribution.

With iOS version 14.5+ uptake now at 81% globally, the long-term picture is much clearer.8 Check out the chart below which shows iOS SDK adoption across the device-base.

Worldwide Post-Launch Adoption of iOS 14.5+ Versions with ATT

Counting drops of water in the desert

Arguing over the small differences in how we measure ATT opt-in rates is like counting drops of water in a growing desert. Beyond the conclusive data already available, another significant issue is that 29% of users have turned off setting on their devices to “Allow Apps to Request to Track.”10 This means that many devices will never get a prompt asking for permission within those apps. We estimated this figure by looking at the percentage of users who “denied” tracking across apps when no prompt was actually delivered. Around 3% of iOS 14+ users worldwide have opt-in prompts turned off by default—such as in the case of devices owned by minors.11

And beyond the opt-in trend, we need to acknowledge Apple’s stalwart intentions to follow through on all of this. If Apple doesn’t get privacy managed the way it envisions through its current efforts, we believe it will keep iterating until it is satisfied. Make no mistake, Apple is committed. All you have to do is look at its recent slick prime-time ad which shows how they come to the rescue in a dystopian world where third-party providers shamelessly siphon any and all data from their iPhone users. Apple has made privacy a core brand value proposition.

Accepting a post-IDFA landscape

It’s time to take a cold, hard look at the IDFA writing on the wall. As an industry, we need to accelerate past the depression and anger stages of IDFA grief. We must recognize that things are going to be different now and move to acceptance so that we can figure out how to thrive in a post-IDFA landscape.

There are promising ways to help rebuild audience targeting and addressability now that the data burden has shifted from the demand side to the supply side. In short, app developers need a scalable way to segment and offer access to their users at the cohort level rather than the individual device level. Meaningful monetization is possible for those who can start adjusting now. We have been investing heavily in this area since last year, and are ready to help publishers. We look forward to sharing more news soon. Keep checking back or just ask us how.


1 Rosenfelder, Shani, “Initial data indicates ATT opt-in rates are much higher than anticipated––at least 39%,”, 8 April 2021,

2, 9 Laziuk, Estelle, “iOS Opt-in rate - weekly updates since launch,”, 5 May 2021, Updated 20 July 2021

3-8, 10-11 Verizon Media, Internal data, 19 July 2021