The fourth beta of the upcoming update to MacOS High Sierra has been released to private as well as public beta testers. The newest build of MacOS 10.13.5 doesn’t specifically call out any new updates or features and comes a week after the 3rd beta was released. The update to the beta build coincides with the update of the beta for iOS 11.4, which released earlier today.
The timing of the fourth beta is a bit strange and suggests that perhaps Apple ran into a significant bug with the 3rd beta released last week. That isn’t 100% certain of course as Apple is notoriously tight lipped about things like that, but the timing suggests it at least.
By now, readers likely know what is coming in 10.13.5 but as a recap, the two major features are Messages in iCloud and AirPlay 2. Messages in iCloud is aimed to be a backup of your messages, including pictures and sound messages, to your iCloud account. This also will save space on your iPhone or iPad. AirPlay 2 is an update to the long-in-the-tooth AirPlay protocol which will allow greater device control once it released.
There is no official word on when MacOS 10.13.5 will land but a safe bet is around WWDC early in June.