Apple has released a new version of macOS High Sierra that brings Messages in iCloud to the Mac. macOS 10.13.5 is now available for all compatible Macs through the Mac App Store.
The macOS High Sierra 10.13.5 update improves the stability, performance, and security of your Mac and is recommended for all users.
This update adds support for Messages in iCloud, which lets you store messages with their attachments in iCloud and free up space on your Mac. To enable Messages in iCloud, go to Preferences in Messages, click Accounts, then select “Enable Messages in iCloud”.
For more detailed information about this update, please visit: https://support.apple.com/kb/HT208723
For detailed information about the security content of this update, please visit: https://support.apple.com/kb/HT201222
Messages in iCloud can be turned on from the preferences section of the Messages app: Preferences → Accounts → Enable Messages in iCloud.
Once enabled, Messages in iCloud has a few benefits. If you delete a message from your Mac, it will disappear from all Macs, iPhones, and iPads running the latest software update. The other benefit is all message history will appear when setting up a new Mac from scratch. This previously required restoring your Mac from a backup.
macOS 10.13.5 is available for all Macs running macOS High Sierra from the Mac App Store.