Apple on Wednesday issued the second beta versions of watchOS 7.2 and tvOS 14.3 to developers for testing.
It is not clear what changes watchOS 7.2 or tvOS 14.3 bring for users or developers. The update for iOS 14.3 was rumored to bring Playstation 5 controller support, so tvOS may get that support as well. The release notes only mention bug fixes for these releases.
In order to update the Apple TV running the developer beta, navigate to the Settings app, select "System," then "Software Update." If you have the appropriate developer certificate installed, the update will be available.
To update the Apple Watch, open the Apple Watch app and select "General" then "Software Update." Place the Apple Watch on the charger and ensure it is above 50% to begin the update.
AppleInsider, and Apple itself, strongly suggest users avoid installing betas on to "mission-critical" or primary devices, due to the potential for data loss or other issues. It is instead recommended to install betas onto secondary or non-essential devices, and to ensure there are sufficient backups of important data beforehand.