I run this mail list. I am in the process of moving it to a new machine; at the same time I am upgrading from mailman2 to mailman3. mm3 is a pain (see below).
I bridge all lists on the domain onto the old machine until I bring this across [ it has been happening for several days ] but things might break when I move this list.
Apologies in advance if things go wrong.
Currently running on mailman2, it was fairly easy to set up and get going; but the s/ware base is ancient (python2) and mailman3 does have some advantages (uses real SQL databases for user info, etc; one instance for all domains; etc).
However the mm3 documentation is crap. Incomplete, wrong in places, assumes that you understand Django, etc, did I mention that it is incomplete ?
Part of the reason for sticking with it is that I can import user rosta from mm2 to mm3 and also mail list history -- although it sometimes screws up.