iOS 17.4 Introduces AdAttributionKit

What Changed

AdAttributionKit is Apple's framework for measuring app ads without identifying individual users. It launched with iOS 17.4 in March 2024, the release that let iPhone users in the European Union install apps from alternative app marketplaces under the EU's Digital Markets Act. AdAttributionKit measures installs from those marketplaces as well as from the App Store.¹ Few alternative marketplaces were live at first, so the immediate effect was small, and AdAttributionKit was designed to run alongside SKAdNetwork without counting the same install twice, so ad networks could support both during the transition.¹

At WWDC in June 2024, Apple published documentation showing AdAttributionKit as the umbrella, as AdExchanger reported, for all its privacy-preserving ad attribution.² App AdAttributionKit builds on SKAdNetwork, its framework for app install attribution, and Web AdAttributionKit builds on Private Click Measurement, its equivalent for the web.

Starting with iOS 18, App AdAttributionKit added re-engagement attribution for click-through ads, so advertisers can see when users who already have an app open it from an ad, and measure the return on specific campaigns. At WWDC 2025 Apple added overlapping re-engagement conversions, attribution windows that advertisers can set by ad type instead of the fixed 30 days for clicks and one day for views, and a country code in postbacks for campaigns with enough volume.³

Why It Mattered

SKAdNetwork had been criticized for being complex, slow to adopt and limited to new installs.⁴ Folding it into a single framework, and adding re-engagement, addressed some of those gaps while keeping Apple's core approach: data is aggregated, delayed and limited by crowd anonymity, so no individual user is identified. For advertisers, the reports themselves changed little at first: AdExchanger found the new framework worked much like the old one, with re-engagement the main addition.²

It also confirmed that Apple's privacy-preserving attribution was here to stay. Rather than relaxing App Tracking Transparency, Apple was investing in its own measurement framework as the sanctioned alternative.