I upgraded OfflineIMAP to 6.5.4 from 6.3.4 so that it will automatically copy new folders to the remote, but I have a problem with folders that already exist locally and remotely.
Suppose MyFolder has 4 messages, both locally and remotely (it's already synced). Then OfflineIMAP will upload the 4 messages from local to remote, and then it will remove the 4 "old" messages from the remote. The result will be that MyFolder will be synced in the end, but with much unnecessary traffic - it was already synced in the first place.