Apple has released the first release candidate of macOS 12.1, iOS 15.2, iPadOS 15.2, tvOS 15.2, and watch OS 8.3 to developers. A release candidate (RC), also known as “going silver”, is a beta version with potential to be a stable product.
Registered developers can download the betas via Apple’s developer portal. Or they can be downloaded over-the-air once the proper configuration profile has been installed from the Developer Center.