iOS 11.4 is officially (and finally) bringing Messages in the Cloud and AirPlay 2 to your iPhone and iPad, long-overdue features announced at last year's WWDC event.
Not only were these features first teased 12 months ago, they were part of several iOS 11 betas, but rescinded from final public software update each update. That all changes with iOS 11.4.
What they can do (and can't do)
AirPlay 2 brings multi-room and stereo HomePod support to match what Google Cast and Amazon Alexa can already do. Apple has caught up with its chief competition.
You now can tell Siri which rooms to play music in, noted The Verge (opens in new tab), but like AirPlay 1, it's very much dependent on your phone. If it dies, the music dies, too.
Google Cast, in our experience, is just a relay device to get a speaker (or TV) to play music from the internet. It require the phone to be on after your tunes are triggered.
Messages in the Cloud, the other big feature, lets you sync iMessages across all of your Apple devices that run iOS and macOS. It backs everything up to iCloud and can free up internal storage and let you delete messages on one device and have it also be deleted on every other device.