Microsoft has had a pretty (ahem) firm policy against offering changelogs for its Surface firmware updates, but that changed today when it released three, one for each of its "pro" Surface devices.
Not all of the updated drivers come with details -- some simply list the driver updated and leave it at that. But the ones that do include some pretty juicy details.
The first, dated October 23, is for the Surface Book. Specific changes include enabling the Windows Hello feature and improving display stability as well as storage performance. Drivers updated with no specific changes listed include camera drivers and the Imaging Signal Processor 2500 driver, among others. The second, also dated October 23, is for the Surface Pro 4, and does the exact same.
Finally, we have the October 26 update for the Surface Pro 3. This one adds support for the Surface Dock and Surface Pro 4 Type Cover, and updates a different set of drivers than those listed for the Book and Pro 4, including the Fingerprint Sensor driver and Keyboard Backlight driver, among others.