Surface Pro 4 devices are receiving a July firmware update. In this rollout, you won’t find any new features and improvements. However, the firmware adds support for the new Type Cover and Signature Type Core featuring Alcantara fabric, which Microsoft made available along with the Surface Pro (2017).
The Type Covers are identical to the previous keyboard, but you can get them in four different colors, including classic black, burgundy, cobalt blue, and platinum.
The new July 2017 firmware update for Surface Pro 4 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.