How to Sync Messages from iPhone to Other Devices (iOS 11.4, macOS 10.13.5)? With the arrival of iOS 11.4 and macOS 10.13.5, I am looking forward to having messages up-to-date across all my Apple devices. The master set of messages lies on my iPhone which I have had the longest. My Mac only has messages from a certain point, and also has many messages shown in mixed up order. 

I want to be able to use my iPhone message history as the 'master ' message history that will be downloaded to my mac. I fear that if iCloud tries to reconcile my iPhone and mac message history some data will be messed up. There are no messages that are on my mac that is not on my iPhone. So, what are the exact steps I can take for this?

(I am in the process of updating iPhone and Mac.)
My goodness!  200GB!?  Unless you have chosen to put a gargantuan amount of data in your iCloud account, I'd recommend paying $.99 a month for 50GB and seeing if that isn't sufficient.  I have 50GB and have used only 13.4GB so far:  photos &amp; videos, Mail, documents, backups, and Messages.