According to this documentation Synchronize messages API users have ability to synchronize messages with pretty simple skipToken mechanics. And it works well for fetching new messages in folders.
But! What I'm also interested is how to sync flags and status like is message read or not. For example I synced all messages from Inbox folder. After that user goes to his Outlook account and reads message and set some flag for this message.
How can I get this info? Should I resync all messages to get only those changes?
Also how I get notion about message removal? If some user deleted message from inbox, how I get to know which message was deleted without fetching all messages again?