The August 2016 firmware update brings driver updates for Surface Pro 4 and Surface Book running the Windows 10 Anniversary Update. According to the Surface Update History support site, this update introduces new changes to four Microsoft drivers to improve battery life in the devices, including:

Surface Management Engine: v11.0.15.1003 improves stability and performance when you change between power states. Surface UEFI: v90.1281.768.0 improves stability and performance when you change between power states. Surface Integration: v1.1.315.0 improves the device usability and battery life. Surface Integration Service Device: v1.0.146.0 makes sure the default Balanced power plan is set correctly when the operating system is updated.

If you have not received the update on your Surface, then manually check by going to Settings > Update & security > Windows Update and try manually forcing the download. Source Microsoft All content on this site is provided with no warranties, express or implied. Use any information at your own risk. Always backup of your device and files before making any changes. Privacy policy info.