- SASL Authentication
- Include code to fetch an OAuth2 token?
- ANONYMOUS
- GSSAPI
- SMTP Client
- CHUNKING (the BDAT command is already implemented and used by BINARYMIME but perhaps the BDAT command could be used always when the server supports the CHUNKING extension to avoid needing to byte-stuff the message?)
- Throw an exception if the MimeMessage is larger than the SIZE value?
- POP3 Client
- Rename Pop3Client.DeleteMessage() to Pop3Client.Delete()? Less verbose...
- IMAP4 Client
- Extensions:
- BINARY
- CATENATE
- LIST-EXTENDED (Note: partially implemented already for getting the special folders)
- CONVERT (Note: none of the mainstream IMAP servers seem to support this)
- ANNOTATE
- METADATA
- NOTIFY (Note: only Dovecot seems to support this)
- FILTERS (Note: none of the mainstream IMAP servers seem to support this)
- LIST-STATUS (Note: only Dovecot seems to support this)
- CREATE-SPECIAL-USE (Note: not widely supported)
- MULTISEARCH (Note: none of the mainstream IMAP servers seem to support this)
- Extensions:
- Maildir
- Thunderbird mbox folder trees