I’m using Apple's Messages on a Mac, an iPhone and an iPad, all set to use my Apple ID for Messages. Since I had accidentally logged out the iPhone a few times, some conversations aren’t in sync – i.e., some messages in a given conversation only exist on the iPhone, but won't show up on the Mac or the iPad. I have found no way of "retroactively" syncing all messages in all conversations. Is this possible at all? Also, let's assume that I buy and setup a new Mac, a new iPad an a new iPhone _from scratch_, i.e., without migrating data or restoring a backup. Now when I log into my existing Apple ID, is there any way to see/retrieve older conversations on the new devices? Put simply: Assuming that I have set Message History to “Keep forever”: Does Apple have a central Messages database that can be accessed from a new device? (I know this does work e.g. for Safari Bookmarks, Calendar and Contact data, but it seems it doesn’t for Messages.) Thanks.