I'm looking for some clarification. The beginning of the article says admins don't need to do anything, but the end of the article talks about DNS text records. Can you elaborate on what is required?
"All outbound Exchange Online email traffic is covered by this new security feature, and there’s nothing admins need to do to leverage it"
"Nothing new is needed from Exchange Online to leverage MTA-STS protection for your own domains"
"To be protected by MTA-STS, a domain owner needs to create the DNS TXT domain record and host the policy file at the required HTTPS URL with a valid certificate that contains their domain. Details about MTA-STS are available in RFC 8461."