Hey, my iMessages where a really mess over the last few years. Every device has shown multiple duplicate conversations etc... So my plan was to make the iPhone the "master". I downloaded 11.4 on it and enabled iMessage in iCloud. Then I downloaded the Updates for my iPad and the MacBook. I deleted all messages before turning on the new feature. The Problem is, that both of the devices won't download the full conversation list of my iPhone! They have different messages and sometimes super old ones instead of the ones written yesterday... But the new ones get synced. I've tried everything from deactivating on all devices to force download it on the MacBook by clicking the start sync button... I hope you can help me!