Google has removed UDIDs — unique device identifiers — from the iOS SDK of its mobile ad platform AdMob to comply with Apple's recent move to phase the ID system out.
Google on Monday released the AdMob SDK v6.4.0 for iOS , which completed its move away from UDIDs that began last September with the release of the AdMob SDK v6.2 for iOS.
Apple dropped support for UDIDs in iOS 6 last September, which it replaced with its new Identifier for Advertising (IDFA). Google supported IDFA on iOS 6 in the AdMob SDK v6.2, but kept UDID for iOS 5 and below. AdMob SDK v6.4 removes UDIDs completely.
Google acquired AdMob in 2009 for $750m, and offers the SDK to owners of iOS, Android and Windows Phone 7 apps who can use display ads within apps and monetise their product.
Developers have relied on UDIDs to track app installations and target advertising to iOS users. However, privacy advocates have campaigned against the use of the ID system since it can be used to identify an owner, directly linking them to their device.
Apple announced in March that from 1 May the App Store would no longer accept new apps and app updates that used UDIDs. That meant older apps that retain UDIDs would be rejected once the next update is submitted to the App Store for approval.
Apple's new Advertising Identifier offered a "non-permanent, non-personal, device identifier", according to the company. However, it was not until Apple's iOS 6.1, released in late January, that users could actually reset the Advertising Identifier. The feature is tucked away in Settings > General > About > Advertising.