Which features will eventually be implemented?

Some known big ones:

• SMTP recipient validation
• TLS
• AUTH
• IPv6
• SPF
• SRS
• DKIM
• DMARC
• ARC
• EAI
• SNI
• DANE
• MTA-STS

Need something else? Tell us about it.

Our roadmap describes our plans in somewhat more detail.

Which implementations won't last forever?

There are many, many patches out there. Needless to say, not all of them meet notqmail's design goals. Two examples of popular, well-loved patches we've personally used and appreciated whose features we hope to provide in other ways:

• The Qmail-TLS patch, because a more qmail-ish design is available: UCSPI-TLS (implemented in s6-networking and ucspi-ssl) extends UCSPI to provide opportunistic TLS for client and server applications in a separate and privilege-separated address space
• Any of the usual SMTP AUTH patches, because a more qmail-ish design is available: Amitai Schleier's acceptutils extends qmail's POP3 authentication architecture to SMTP and OFMIP, enabling new user-controlled features

See also Designs.