“These builds are from the 20H1 development branch. Some things we are working on in 20H1 require a longer lead time,” explained the company. “We will begin releasing 19H2 bits to Insiders later this spring after we get 19H1 nearly finished and ready; once 19H1 is ‘nearly finished and ready' we'll also use the Release Preview ring for previews of drivers and quality updates on 19H1.”
No Going Back
It's hard to argue with the company's logic here. A longer testing period should help to reduce critical bugs found in the previous release while letting Microsoft get more feedback on major changes.
However, it's well worth noting that this build is not for the faint of heart. Though Microsoft always recommends users don't use Insider releases as their daily driver, some do. Windows 10 20H1 is likely to be buggier than usual, and senior program manager Brandon LeBlanc says you won't be able to roll back.
“Once you start taking 20H1 builds in Skip Ahead you cannot downgrade,” he explained on Twitter.
That seems to indicate that Fast Ring insiders will be getting Windows 10 19H2 builds for now, with 20H1 dedicated to Skip Ahead.
Meanwhile, Windows 10 191H is nearing completion. The next major feature update promises a Light theme, software-based encryption, and fast music controls. Currently, 20H1 isn't much different to 191H, but it'll be interesting to see how it evolves over the next year.