I've been using Thunderbird for a few years, and have accumulated ~2GB of mail locally. My mail service is being migrated to an externally hosted Exchange server with ample storage. I'd like to migrate all my old messages to that server, where they will remain. Is there a way to do this?
I care mainly about migrating the messages, and their folder structure if at all possible. I'm not concerned with contacts or any secondary stuff from Thunderbird.