Today Microsoft has posted a warning for Windows 10 Insiders in the Fast Ring.
With the coming release of Windows 10 May 2019 Update to Release Preview Ring, Microsoft is set to move all Insiders in the Fast Ring to Windows 10 20H1, which Microsoft notes “may contain bugs that might be painful for some.”
Insiders who are already on 20H1 due to being in Skip Ahead will also be demoted to Fast Ring as they are merged with the rest of the Fast Ring.
Microsoft notes that if you want to get off the train before it hits 21H1 now would be a good time to switch to the Slow or Release Preview Ring.
Microsoft is still planning Windows 10 19H2 for later in the year and will adjust the rings accordingly when the first builds hit.