T-Mobile has just pushed out BlackBerry OS 7.1 to RIM's Bold 9900 and Torch 9810, providing both handsets with some new features in the process. First unveiled back at CES, the latest software revision includes native support for Wi-Fi calling, mobile hotspot / USB tethering, BBM Music, and Bing search. Further, it's worth noting that this update brings compatibility with the Commercial Mobile Alerts System (CMAS) to both devices, a mechanism that can provide safety information when emergency situations arise. For those prone to the occasional snag or two in the day-to-day use of either BlackBerry, there's now a built-in diagnostics tool that can help stamp out issues without the need to contact customer support. The usual suite of optimizations and security fixes are also in tow. BlackBerry OS 7.1 can be installed either over the air or by loading the update directly via desktop manager for both PC and Mac.