According to the Microsoft changelog for the Surface Pro 3 Update History support page, these are the new changes:

Surface Pro Embedded Controller Firmware: 38.13.50.0 improves battery life during sleep. Surface Pro UEFI: 3.11.2150.0 improves PXE performance on IPv6.

The new June 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.