Apple has reached the fifth round of betas for its operating systems, with new developer builds of iOS 12.3, tvOS 12.3, watchOS 5.2.1, and macOS 10.14.5 available for testing.
The latest builds can be installed onto devices enrolled into the test program via an over-the-air update, or via the Apple Developer Center. The public beta counterpart usually arrives within a day or two of the developer version, and can be acquired from the Apple Beta Software Program website.
The fifth beta of iOS 12.3 is build number 16F5155a, up from the fourth build 16F5148a. The fifth tvOS 12.3 beta, build number 16M5151a, replaces the previous build number 16M5146a. Apple's fifth build of watchOS 5.2.1 is build number 16U5113a, overtaking from 16U5110a. Lastly, macOS 10.14.5's fifth build is number 18F131a, in place of the fourth build 18F127a.
There is also a new fourth beta for Apple TV Software 7.3, for the third generation Apple TV. Build 12H841 replaces the third build 12H836.
The new betas replace the fourth builds issued by Apple on April 29.
The chief change in the betas relate to redesigned Apple TV experience, with tvOS 12.3 and the TV app in iOS 12.3 laying the groundwork for the upcoming launch of Apple TV Channels and the Apple TV+ service arriving later in 2019. Another big change is in the iOS Wallet app, in preparation for the Apple Card launch in the US this summer, with additional features arriving specifically with the card in mind.
The existence of beta builds for the Apple TV Software indicates Apple will be bringing its Channels and Apple TV+ experience to the third-generation Apple TV. It is likely an indication Apple wants to bring the new services to as many users as possible, even those on legacy hardware.
AppleInsider, and Apple itself, strongly recommend users don't install the betas on primary devices or hardware they deem as "mission critical" at all, as there is the highly remote possibility of data loss or other issues. Testers should instead install betas onto secondary or non-essential devices as a safer alternative, and to always make sure there are sufficient backups of important data before updating.