Thedoes a lot of things, but battery life hasn't been its strong suit. A new software update that hit today might help for those who use the Band 2 with GPS on for outdoor workouts.
According to Microsoft's blog, a new GPS Power Saver mode will extend battery life while GPS tracking is on, for up to 4 hours. But it does this by pinging GPS less frequently, a trick used by other fitness trackers. The problem could end up being less accurate location tracking, although we haven't yet used it.
Regardless, the firmware update and a Microsoft Health app update that adds weight and BMI tracking (provided you manually enter your weight) are available now.