If emails are encrypted at rest, as in the cases of Tutanota or ProtonMail, IMAP cannot be used as it is. In fact ProtonMail offers a bridge app for desktop, which interacts with PM servers, decrypt the emails and offers a local IMAP server so you can use Thunderbird, etc.
If emails are encrypted at rest, as in the cases of Tutanota or ProtonMail, IMAP cannot be used as it is. In fact ProtonMail offers a bridge app for desktop, which interacts with PM servers, decrypt the emails and offers a local IMAP server so you can use Thunderbird, etc.