The firmware update is available immediately for devices running the Windows 10 Creators Update and later, and these are the full list of changes:

Marvell AVASTAR Bluetooth Radio Adapter: 15.68.9125.57 improves system security. Marvell AVASTAR Wireless-AC Network Controller: 15.68.9125.57 improves system security. Surface Integration Service Device: improves system stability. Surface Touch Servicing ML: improves pen and touch performance.      Surface Touch: 429.0.1.10 improves pen and touch performance. Surface UEFI: 234.2291.769.0 improves driver installation servicing.

The update should download and install automatically, but if you have not received it on your Surface, then you can 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.