Apple is planning to give developers a new way to keep track of users, replacing the now-deprecated Unique Device Identifier (UDID), according to sources speaking to the Wall Street Journal. The sources don't appear to have explicitly named WWDC as the venue for the announcement, but the tool is supposed to be more privacy-conscious and is expected to be detailed "in the coming weeks."

Concerns over apps storing and making use of iPhone, iPad, and iPod touch UDIDs began popping up in 2010 when security researchers discovered that many apps were transmitting user data back to their own servers. Some of those apps associated real names in plaintext with the device's UDID, but even without a specific user name or address, the device's UDID could be associated with the collected data and the user in question could be identified. Other apps were later discovered to be uploading user data to their servers, eventually getting the attention of Congress.

Developers and marketers have made use of the UDID in order to target their services to specific users, but Apple began warning developers to avoid using it with the release of iOS 5.0 in October of 2011. In March, the company began rejecting apps that still used it. The WSJ has virtually no details on what the new system will be like, but wrote, "One of the people briefed said that the new anonymous identifier is likely to rely on a sequence of numbers that isn't tied to a specific device."