After releasing a cumulative update for Windows 10 PCs on the Slow ring yesterday, Microsoft is now offering another to the Fast ring. Build 16232.1004 is now available, and there's just one new feature: a new version of Notepad.
It's not clear if there are actually any new features in the updated binary, as the firm didn't mention any. Notepad is a pretty basic application though, so you probably shouldn't expect any.
Microsoft says that the "primary goal of this update is to test our servicing pipeline", and one thing that's different about the way that this update is distributed is that you won't have to reboot your machine after installing it (unless you have Notepad open). While there obviously have been cumulative updates that don't require a reboot, this one actually changes the build number.
There are a couple of known issues to be aware of:
Make sure you’ve setup Mixed Reality before taking this update.
After installing a language pack or feature-on-demand like .NET 3.5, your PC may be offered this update again and fail.
The company also made a note of saying that this update will only be available until the next Fast ring build is out, which could be as early as tomorrow, since there haven't been any new builds since 16232 was released last week.