After releasing iOS 12.3 and its other operating system updates to the public on Monday, Apple has restarted the beta testing process once more, this time issuing the first builds of iOS 12.4, tvOS 12.4, watchOS 5.3 and macOS 10.14.6 to developers for testing.
The new builds can be acquired by developers in the beta as an over-the-air update on devices already enrolled into the program, or through the Apple Developer Center. Public beta variants of each operating system normally surface a few days after the developer betas, and can be accessed from the Apple Beta Software Program website.
The first developer beta of iOS 12.4 is build number 16G5027g, replacing the last and sixth iOS 12.3 beta build 16F5156a. The new tvOS 12.4 beta's first build is 16M5526d, taking over from the fifth tvOS 12.3 beta, build 16M5151a. The first watchOS 5.3 build 16U5526fupdates from the fifth watchOS 5.2.1 build, 16U5113a. Lastly, macOS 10.14.6's first build is number 18G29g, up from the fifth build of macOS 10.14.5's beta, build number 18F131a.
It is currently unclear what exactly users can expect to see in the latest betas, but release notes and testing of the new builds will take place shortly after they are issued.
Of the most recent launches, iOS 12.3 and tvOS 12.3 benefited from the main changes, centering around the new Apple TV Channels experience in the TV app. Users can now subscribe to individual channels from the app and the Apple TV, as well as being able to share the subscription with up to six family members, and benefit from recommendations of shows and movies from more than 150 video apps and streaming services.
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.