Developers who attempt to circumvent Apple's own Advertising Identifier
with other methods to track users and ad impressions may now find their apps rejected
by the App Store. The company is now -- nearly two years after announcing that it would be abandoning the former Universal Device Identification (UDID) method
for ad tracking -- enforcing developer guidelines that mandate the use of Apple's Advertising Identifier (which can be turned off by the user) as the main allowable ad tracking standard for ad networks.