Following the early second beta build of iOS 12.4, Apple has issued new developer betas for its operating systems, with a third build of iOS 12.4 now available for testing alongside second builds of tvOS 12.4 and watchOS 5.3.
The latest beta versions can be acquired from the Apple Developer Center by participants in the Developer Beta program, or as an over-the-air update for devices already using the betas. Public beta versions arrive within a few days of the developer versions, accessible via the Apple Beta Software Program site.
The third developer beta of iOS 12.4 is build number 16G5038d, up from 16G5027i used for the previous build. The latest second tvOS 12.4 beta is build 16M5537c, replacing the first with build number 16M5526d. The new watchOS 5.3 build is 16U5537b, taking over from the first build, 16U5526.
The new betas follow the earlier issuing of the second iOS 12.4 developer beta build on May 20, and the first builds of macOS, tvOS, and watchOS on May 15. Given that iOS 12.4 is already out of step with the other three, it is possible that the gap could be widened further if Apple elects to issue even more iOS betas.
It is unlikely that there will be any real visual changes made to any of the builds, with the bulk of features and new additions likely to be saved for a future release, one that could be announced at WWDC in June. The version updates are likely to be made up of bug fixes and performance improvements.
It is probable that iOS will see most of the alterations, albeit in a background manner that doesn't affect the users directly, as preparation for the launch of upcoming services. For iOS in particular, the Wallet app has to be made ready for the launch of Apple Card, the co-branded credit card that will go live this summer in the United States.
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.