Overview
- This week Apple deployed iOS 27 WebKit changes that stop many adtech domains from accessing advertising identifiers and in some cases prevent those vendors from serving ads in iOS browsers.
- The list of affected domains reportedly included The Trade Desk, ID5, LiveRamp, Permutive and Audigent, causing immediate bid drops and broken ad delivery for publishers that rely on those partners.
- The Trade Desk filed a bug report after being blocked and Apple told the company it adjusted the block in the iOS 27.2 beta, but that beta fix is not yet broadly available so disruptions will likely continue until the public 27.2 release.
- Reporting says Apple can update the block list remotely without an OS release, which creates sudden operational risk for vendors and has pushed some publishers to test server‑side solutions such as IAB Tech Lab’s Trusted Server to keep ad auctions working.
- Industry observers warn the move will redirect ad spend toward platforms with rich first‑party data, pinch publisher revenue on the open web and prompt scrutiny over whether Apple’s control of the list gives it an unfair advantage.