I used to have a bookmark for a page that showed the currently supported versions of Postfix and (I think) when support ended for previous versions). I seem mohave lost the bookmark and I can’t fin the page on postfix.org which makes me think it isn’t there.
I can get the information by going to <http://www.postfix.org/announcements.html> and looking in specific announcements to see what (if any versions) were obsoleted. Just as an example, I was trying to find when 2.6 support ended, and after going through he major releases I found it in the 2.10 release announcements. But what I remember seeing was a page that listed release dates and EOL dates. -- Apple broke AppleScripting signatures in Mail.app, so no random signatures.