I've asked DH Support twice now to install a newer version of GNU MailMan. Sadly, upgrading the 2.5 year old version of MailMan 2.1.17 is not yet a priority. They don't seem to understand what is wrong with 2.1.17. We need to tell them directly, in a support ticket.
Mailman 2.1.17 does not include any information of who the message was sent from WHEN the user has not properly configured their email client with a person name. Every time certain people send a list message, no one knows who it is from. It is a constant problem that DH has the ability to fix by upgrading to any newer version of MailMan.
Mailman 2.1.17 always discards the from email address, which is also a problem. Pre-DEMARC versions of MailMail did not discard the from address. I well understand the problems that the whole DEMARC thing has caused, but rather than continue to whimper & cling to victimhood, we need to bravely move forward.
Later versions of MailMan repaired these flaws.
Please DreamHost, upgrade to a later version of MailMan. This is really important to the groups that use MailMan.