Before beginning the migration process, it is important to ensure that your environment has been prepared and that all requirements have been met.
Due to the varying requirements and processes we have broken these down between types of migrations.
PST-based migrations are not documented as they are merely a file import procedure which requires no preparation.
In order for Exchange Online to access your IMAP sever/service, it must be accessible via the IMAP protocol from the Internet, which is generally the case.
It is important that the users be created via the Office 365 administrative interface either individually or in bulk.
You also need to prepare a listing of existing IMAP mailboxes in CSV format ...