iOS 11.4 Beta 2 Released for Testing
Apple has released new beta versions of their various operating systems, including iOS 11.4 beta 2, tvOS 11.4 beta 2, and watchOS 4.3.1 beta 2.
Presumably, macOS 10.13.5 High Sierra beta 2 will arrive shortly for Mac beta testers.
iOS 11.4 beta appears to be working mostly on bug fixes and minor enhancements to the mobile operating system, though iMessages in iCloud is also being tested again after being yanked from iOS 11.3 before its release to the general public.
Users enrolled in the various Apple system software beta testing programs can find the latest versions available now through the Software Update mechanism of their enrolled devices. Typically the developer beta builds are made available first, and followed soon after by the public beta versions.
For iOS, going to Settings > General > Software Update will reveal the iOS 11.4 beta 2 update.
tvOS can be updated through the Apple TV Settings app, and watchOS can be updated through the synced iPhone Watch app.
For non-beta testers, the various final versions of system software available for Apple products are currently iOS 11.3 for iPhone and iPad, tvOS 11.3 for Apple TV, watchOS 4.3 for Apple Watch, and MacOS 10.13.4 for Macs with High Sierra.