According to the Microsoft changelog in the Surface Pro 3 Update History support page, these are the complete list of changes.

Intel HD Graphics Family: improves Miracast and docked video performance. Intel Display Audio: improves Miracast and docked video performance. Surface Pro UEFI: 3.11.2050.0 improves system performance for the latest Windows versions.

The new January 2017 firmware update for Surface Pro 3 should download and install automatically. However, if you have not received the update on your Surface, then go to Settings > Update & security > Windows Update and try to force the download manually. 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.