The cumulative January 2017 update KB3209835 for Windows 10 brings the OS version to 14393.594. However, the support page is not available yet and there is no information about what build 14393.594 is changing in the system.
What we do know is that it requires an OS restart for a successful install. It's a PC only update so far, with no matching update yet for Windows 10 Mobile devices. We will keep you posted on everything as it happens.
Windows 10 Build 14393.594: No big changes
Cumulative updates are the quiet types, bringing simple bug fixes, various OS optimizations, and general user improvements. New features are not a part of the usual package so no big changes are to be expected.
Still, if the update goes through without any major problems, it should arrive at the Production ring sometime in the next two weeks. Furthermore, if you are among the users in the Release Preview ring, you can download the update by heading over to Settings > Update & security > Check for updates.
You can also download KB3209835 directly from the following links: