Email migration is the process of moving email between two servers. You may want to do this because you’re moving from one email service to another, or because you’re migrating from one of our plans to another in a manner that did not allow simply upgrading (like moving to a promotional package). Please note that we do not perform migrations on your behalf, and if this article does not answer your specific question about migration then we most likely do not have an answer to your specific scenario and would recommend that you reach out to your local IT specialists.
We recommend using imapsync to perform this task. This can be done via web interface, Windows application, or command line (Linux best documented).