Today, Microsoft released this week's Windows 10 Insider Preview build to the Fast ring.
As has been the case for months now, build 19640 does not have any new front-facing features.
This is because it comes from the mn_release branch, and we'll have to wait for rs_prerelease builds to return before we see more new features.
As for build 19640, here's what's listed under general changes and improvements: And here are the known issues: While this is what it would look like when Microsoft is starting to finalize a feature update for release, that's not what this is.
This is more or less Microsoft just going through the motions that it usually goes through until prerelease buidls ramp up again.