Is there any standard out there for trying to create some "future" mail? Ideally it would handle--or emulate--old email clients until they had time to be upgra

Is there any standard out there for trying to create some "future" mail? Ideally it would handle--or emulate--old email clients until they had time to be upgraded but is this even under consideration now? I think now more than ever we should evaluate SMTP and see what we can do to either secure it or replace it. Looking at a barebones SMTP server in Node.js I could see some ways to very easily encrypt all data but that only goes so far.. you're still receiving the normal mail headers you would get with any other platform.. I think we need to get at this data but I am so far unaware of a solution to this beyond basic TLS. Thoughts?