To migrate IMAP emails to other file formats, webmail apps, utilize the smart IMAP Backup tool that can simply backup IMAP files to other file formats, webmail apps. It is simple to access for everyone. The IMAP Backup tool for Mac, Windows, supports multiple IMAP accounts for backup at once. Using the tool, you can migrate IMAP data to PST, PDF, MBOX, IMAP Server, EML, EMLx, Gmail, Office 365, Exchange Server, Outlook.com, Yahoo Mail, etc.Use its free demo edition to know about how to backup IMAP files to another cloud account or file format without any cost.
https://www.cubexsoft.com/imap-backup/
If you are looking for a solution to
backup IMAP emails for Mac then I would recommend you to use
Mail Backup Tool on your system. The software is compatible with both Mac and Windows operating systems. With this utility, you can save complete IMAP mailbox at once. It offers various saving options to download IMAP emails into multiple formats such as PST, PDF, MBOX, EML, etc. It preserves data integrity and folder hierarchy as well during the process. Apart from this it also provides various advanced filter options for selective backup. It is designed in such a way any novice user can easily use it without facing any issues.