"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AT&T Activates 8.6 Million iPhones in Q4 2012, Device Accounts for Some 84% of Smartphone Sales
During the same holiday quarter, Verizon activated 6.2 million iPhones, some two-thirds of its total smartphone sale. AT&T's previous best quarter was 2011's fourth quarter, when it activated a total of 9.4 million smartphones and 7.6 million iPhones -- an 80% share for the Apple device.
On Twitter, Apple watcher Sammy the Walrus calculated that 74% of smartphones sold by AT&T and Verizon were iPhones, giving the device an "iPod-like share".
Update: AT&T has reached out to us to note that the 8.6 million iPhone number is activations, while the 10.2 million smartphone sales number is sales. This means the iPhone probably doesn't make up exactly 84% of smartphone sales, but it should be in the right ballpark. The activations number includes hand-me-down iPhones and the like.