For starters, Microsoft has confirmed that users previously on the Fast ring will not be delivered builds of Windows 10 19H2 (2019, Second Half). Instead, they will be shifted to Windows 10 20H1 development builds, which is scheduled to land around this time next year. For those that are up to the challenge, Microsoft does present this warning:
20H1 builds are from our development branch (RS_PRERELEASE) and as is normal with builds early in the development cycle, these builds may contain bugs that might be painful for some. If you are in the Fast ring and your PC gets updated to 20H1, you won’t be able to switch your ring to the Slow or Release Preview rings without doing a clean-install on your PC and starting over.
So where does this leave Windows 10 19H2, now that Windows 10 19H1 (May 2019 Update) development has pretty much wrapped up? Microsoft says "we will begin releasing 19H2 bits to Insiders later this spring and will talk more about what that will look like in the near future."
Why Microsoft is pushing users to next year's release so early instead of focusing first on Windows 10 19H2 -- which will be released first -- is a mystery to us, but there must be some "master plan" that the company has in mind with this strategy.
Microsoft first made the puzzling move back in mid-February when the Skip Ahead ring started pushing out Windows 10 20H1, which was a two-version jump. With this new reassessment of its ring structure, the Skip Ahead and Fast rings are now essentially being merged into one.
Confused yet? It will be interesting to see which track Windows 10 19H2 will take once those aforementioned "bits" are available to testers. We're assuming that once released, the Fast and Skip Ahead rings will once again be separated, with the former being reserved for Windows 10 19H2.