https://wccftech.com/beta-channel-can-now-install-windows-10-version-21h1/

Microsoft has introduced the next feature update for Windows 10, naming it version 21H1. The company is bypassing tradition and releasing 21H1 as a minor update, similar to H2 feature updates. Microsoft said that it understands the "importance of providing the best possible update experience to help people and organizations stay protected and productive," which is why for the first time ever, an H1 feature update release will be delivered in an optimized way using servicing technology. In short, it will be delivered like a cumulative update for devices running versions 2004 and 20H2.

While public users will have to wait a few more months (probably until at least May), Beta Channel Insiders can now install Windows 10 21H1 - if they want to do so. The new feature update is available for them via the "seeker" experience, which means they will need to head over to the Settings app > Update & Security > Windows Update and choose to install Windows 10 21H1.