Apple has moved on to the fourth round of developer betas, providing app makers with fresh builds of iOS 15.2, iPadOS 15.2, tvOS 15.2, and watchOS 8.3.
The newest builds can be downloaded via the Apple Developer Center for those enrolled in the test program, or via an over-the-air update on devices running the beta software. Public betas typically arrive within a few days of the developer versions, via the Apple Beta Software Program website.
The fourth-round builds follow the release of the third-round versions, which Apple provided to developers on November 16. The second round was on November 9, and the first occurred on October 27.
All The NEW Features in iOS 15.1 & iPadOS 15.1! Now Released!
The iOS 15.2 and iPadOS 15.2 fourth developer betas carry a build number 19C5050b, replacing the third build, 19C5044b. The fourth tvOS beta is build number 19K5050a, the watchOS 8.3 has a build number of 19S5050c, and a new version of Apple's HomePod software has a listed build number of 19K5050a.
AppleInsider, and Apple itself, strongly recommend users don't install the betas on to "mission-critical" or primary devices, as there is the remote possibility of data loss or other issues. Instead, testers should install betas onto secondary or non-essential devices, and to make sure there are sufficient backups of important data before updating.
Source: Appleinsider