Nice! MTA-STS is for the email space what HTTP Strict Transport Security (HSTS) is for websites. This RFC has been around for a bit, and if I understand correc

Nice! MTA-STS is for the email space what HTTP Strict Transport Security (HSTS) is for websites. This RFC has been around for a bit, and if I understand correctly was recently moved to the status "Proposed Standard" from "Internet-Draft". I'm glad to see email security continuing to move forward. Thank you to the people who put what was undoubtedly considerable time into making this a reality. Question to those who are more knowledgeable: Is there a way to determine whether a particular inbound connection is respecting a domain's MTA-STS policy? It'd be nice to be able to monitor what percent of incoming connections are MTA-STS aware, as a way to measure adoption.