Samsung is just rolling the update for the battery maintenance to all variants of the Gear S2 in the US. This update includes some major battery life optimizations, in addition to the usual plethora of bug fixes and speed optimizations.
Installing an update on the Gear S2 is a little different to the that of a smartphone or tablet. To get this upgrade, you’ll have to launch the Samsung Gear application on your handset, then navigate into Settings, followed by About Gear and tap the Update Gear button. You will then notice the upgrade download in the background and install on your watch.