https://www.cnet.com/news/messages-in-icloud-now-available-on-mac-with-macos-10-13-5-update/

It's a lot later than we expected, but it's finally here -- with today's download of MacOS 10.13.5 (via 9to5Mac), the Messages in iCloud feature has arrived to keep your texts and shared photos in sync across all your Apple devices. So when you delete a message on your Mac, it'll be gone from your iPhone, too.

Wait, didn't we just report that two days ago? Kinda -- that's when iOS 11.4 arrived to bring that feature to iPhones and iPads. This is the other shoe dropping to bring the feature to Macs as well. Because it's kind of hard to release a new feature for your Mac without your Mac actually downloading something.