Update 11/13/2023: We added new information on how to know when this change is released to your organization.
Today, we are announcing an update to our requirements for SMTP relay through Exchange ...
Updated Feb 22, 2024
Version 19.0
Blog Post
Carolyn_Liu
Microsoft
Microsoft1) In case of automatic reply mails, connector validation mails that do not have a return path(<>), will they be impacted?
Answer: Yes if your connector is using IP, or the connector is using certificate, but domain in the certificate is NOT an accepted domain.
2) To fix this, we are making a code change to set the P1 header to P2 header.(so that P1 header or return path is not empty).
For example, if there is a connector validation mail, the from header(P2) will be "email address removed for privacy reasons" and P1 header will be <>.
Now, we set the P1 heder to 'email address removed for privacy reasons' . Is this approach fine?
Answer: If the domain in P1 address is an accepted domain, then the approach is fine.