Starting May 1, 2013, the Apple App Store will no longer accept new apps or app updates that access UDIDs. Apple required developers to update their apps and servers to associate users with the Vendor or Advertising identifiers introduced in iOS 6. More details can be found in the UIDevice Class Reference.
As of version 1.3.125 of the Webtrends iOS SDK, this was resolved with by adding back the capability to configure the visitor id using the wt_dc_id_method configuration setting (Webtrends.plist). Developers may now use UDID replacements introduced by Apple in iOS6. Permissible values are:
vendor_id* – Use Apple’s Vendor Identifier. Same identifier for all apps from a given publisher on the device.
advertising_id* – Use Apple’s Advertising Identifier. Same identifier for all apps on the device.
custom_id – Use a randomly generated identifier. Different identifier for all apps on the device.
* Introduced by Apple in iOS 6. If app is running on earlier version of iOS, fallback to custom_id. Developers must add AdSupport.Framework to your app to get this functionality.