Apple released .1 Beta 2 on December 12 with Build number 9B5127a. The current beta now uses build number 9B5141a.
iOS 5.1 beta 3 restores a sought after feature by many users, Enable 3G. The Enable 3G toggle allows users to completely shut off their cellular data, something that is currently unavailable. iOS users who use WiFi at work and home, experience heavy battery loss due to the fact that 3G and WiFi are running simultaneously. With this new feature, users can simply switch off 3G and use WiFi and can switch on WiFi just as easily. Apple noted under the toggle feature, that "3G offers faster data speeds but uses more battery power than EDGE".