https://www.pcgamer.com/windows-insiders-can-already-download-the-next-big-update-to-windows-10/

Microsoft is pushing out a new test build of Redstone 5, the next major upgrade to Windows 10 that will likely release this fall, to members of its Windows Insider program. The latest preview build (17672) is relatively minor in terms of new features, though it does contain a host of bug fixes.

In case you're not familiar, Microsoft's goal is to upgrade Windows 10 twice a year with major updates. Here is a list of the major builds that have been released to date, starting with the launch of Windows 10 three years ago: