@PlexSheep@infosec.pub I don't think you understand how Proton stores email on their servers. STARTTLS, imaps, and smtps all encrypt during transport, but would require the server to have a decrypted copy. Since they use zero-access encryption to store emails, that's not possible.

See https://proton.me/support/proton-mail-encryption-explained

@PlexSheep @MrPoopbutt SMTP and IMAP are impossible since they can't decrypt your data. They do have https://proton.me/mail/bridge to enable you to use those protocols, however.