I have been setting up a server for a mailing list I created for harpsichord discussion. It took three months full time work by me to set up all the open source software. So I have deep knowledge of this area currently. A large part of the technical difficulty is actually getting mails out through the complex world of spam blacklists, and DMARC is a huge and very difficult and complex part of this, along with SPF and DKIM. The change that is being made here is clearly necessary to me, and explains some of the list issues people were having lately. Sadly, it's probably unintelligible to non-experts.
But classifying mail into folders for this list is trivial - just make a filter rule on the To: header. I have used that just fine for years. Any mailer can do that nowadays. Andrew
