Apple has in the past discouraged developers from using unique device identifiers known as UDIDs, but has now set a firm date on when they'll be banned altogether.
From 1 May, Apple will block any apps or updates to existing apps that use UDIDs - a key piece of analytics systems which publishers and developers use to target advertising and track apps.
"Starting May 1, the App Store will no longer accept new apps or app updates that access UDIDs. Please update your apps and servers to associate users with the Vendor or Advertising identifiers introduced in iOS 6," Apple said in a developer update.
The cut-off date for UDIDs should come as little surprise to iOS developers who have been warned of Apple's intention to move away from having them included in apps. The company has come under pressure from privacy advocates and legislators in the US because UDIDs establish a permanent connection to a specific piece of iOS hardware, and could therefore be linked to its user.
In March last year, Apple began blocking some apps that used UDIDs, ZDNet's sister site CNET reported at the time. The impetus to do away with UDIDs became greater after hackers released a file containing a million UDIDs and their associated user names. Although AntiSec hackers claimed the leak came from an FBI laptop, the source of the leak was later revealed to be the publisher BlueToad, whose systems were hacked.
Apple dropped support for UDIDs with the release of iOS 6 in September 2012 along with a replacement feature called Advertising Identifier.
Advertising Identifier offered a "non-permanent, non-personal, device identifier". 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.
Starting 1 May, Apple will also require that all apps and app updates be built for iOS devices with Retina display and that the iPhone apps must also support the 4-inch display on iPhone 5.