- LTE support for more carriers
- Purchase movie tickets through Fandango with Siri (USA only)
- iTunes Match subscribers can now download individual songs from iCloud
- New button to reset the Advertising Identifier
While the new 70MB update includes LTE support for LTE in at least 16 new countries, iLounge points out that the new carriers are only supported by the iPad 4, the iPad mini, and iPhone 5. While iOS 6.1's enhanced LTE support has been grabbing most of the attention, it's new privacy option deserves a closer look.
In addition to several security updates, iOS 6.1 contains a new button labeled "Reset Advertising Identifier" in Settings > General > About > Advertising.
The Universal Device Identifier (UDID) -- a 40 character string of letters and numbers -- was commonly used for advertising and user tracking in iOS. But Apple dropped support for the UDID when it released iOS 6.0 in September 2012 and replaced it with a new feature called the Advertising Identifier.
Unlike the UDID, which could be tied to a specific iOS device's hardware (and its user by extension), the new Advertising Identifier does not contain any device information and isn't permanent.
Apple described the new Advertising Identifier like this when iOS 6.0 was released:
iOS 6 introduces the Advertising Identifier, a non-permanent, non-personal, device identifier, that advertising networks will use to give you more control over advertisers’ ability to use tracking methods. If you choose to limit ad tracking, advertising networks using the Advertising Identifier may no longer gather information to serve you targeted ads. In the future all advertising networks will be required to use the Advertising Identifier. However, until advertising networks transition to using the Advertising Identifier you may still receive targeted ads from other networks.
While Apple provided the ability to Limit Ad Tracking in iOS 6.0 (above) the Advertising Identifier was static. Apple changed this today in iOS 6.1 by adding the ability to reset the Advertising Identifier with a handy new button (pictured above). Users concerned about having their personal usage habits tracked by apps and advertisers now have a convenient button to reset the identifier, essentially making them appear like a new user.
While iOS 6.0's Limit Ad Tracking feature was akin to your web browser's Do Not Track option, resetting the Advertising Identifier is analogous to deleting your browser's ad tracking cookies.