After five test versions, the watchOS 4.3.1 (compilation 15T567) and the tvOS 11.4 (15L577) as well as iOS 11.4 (separate post) are also now available for download.
Of interesting news we have, in watchOS, a new incompatibility alert for old apps and bug fixes (like one that made the screen stuck on the apple, during startup); on tvOS, apparently, we only have improvements and general fixes, as well as compatibility with AirPlay 2.
Before starting to download watchOS 4.3.1, open the Watch app on your iPhone and, in the ?My Watch? tab, go to General Software Update. Make sure your Apple Watch has at least 50% battery left. When the update is actually going to be applied, I need it to be connected to power. You don't have to worry about backup, as this is done automatically on your iPhone.
There is no significant news in tvOS 11.4. To update your Apple TV, there is no mystery: open the Settings app, go to System and then Software Update. Everything done OTA (over-the-air), that is, by air; the time for the update to be applied depends mainly on your internet connection.
In addition to them, Apple also released to developers today the Xcode 9.4 (compilation 9Q1019a). For now, no release of the final version of macOS High Sierra 10.13.5.
Version 11.3.1 (7.8 GB) Requires macOS 10.14.4 or superior
Update 05/29/2018 s 15:47
Apple also released the iTunes 12.7.5, which brings performance improvements and general corrections.
The update is available through the Mac App Store and should soon also be painted on the iTunes page, on the Apple website.