If you are looking for an IMAP to IMAP migration tool ,then
TrustVare IMAP to IMAP Migration Tool is a great option to move emails directly between two IMAP accounts. All you need is the login details of your source and destination mailboxes, so you don’t have to export emails to an intermediate file first.
I used it to move a mailbox to a new email provider and the migration was simple. It moved my inbox, sent items, drafts and other folders, without disturbing the folder hierarchy, attachments and email properties. The date filter was also useful for me as I only needed to migrate recent emails and not the whole mailbox. The software created a log file after the migration, so I could easily see that everything had transferred successfully.
It’s a practical solution if you’re switching between Gmail, Office 365, Yahoo, iCloud, AOL or any other IMAP enabled service and want to move your mailbox with minimal manual work.