I was recently checking my MIAB box against a couple of online sites to verify the server settings.
To make a short story, short, I updated my smtp_banner setting in the postfix main.conf file to just include the host name. I removed the reference to MIAB and the Ubuntu version. I still think this conforms to standards. If not, I’m sure someone will let me know.
As far as I’m concerned, the less information the bad guys have, the better.