https://wccftech.com/apple-releases-ios-11-4-with-messages-in-icloud-airplay-2-more-complete-changelog/

Apple has finally released the end-user version of iOS 11.4 for iPhone, iPad and iPod. It features Messages in iCloud, AirPlay 2 and few other changes which are highlighted in the official changelog.

iOS 11.4 is a very important update for a couple of reasons. First of all, it brings Messages in iCloud to everyone, a feature which was shown off last year at WWDC 2017. What it does is essentially sync your messages with Apple’s servers so that every single device of yours has the Messages app working in complete harmony. If you delete one message from a device it will be gone from the other. Even if you delete an entire thread, the change will be reflected on every single device you’ve signed into. It’s pretty cool.