In December 2023 on this list, Vasilij Schneidermann advised:

> one not so obvious thing is that in the wild, the overwhelming
> majority of projects uses mailman2. mailman3 is a complete rewrite with
> a different user interface. It's best to treat them as separate
> projects when evaluating a solution.

At that time, nobody volunteered to try installing Mailman 2. It was
unclear to me where to find it, how to install it on a modern Linux
distro, and most important of all, what its security status is. Recent
versions of Debian package the bloated Mailman 3 only.

Retropikzel just asked me about mailing lists so I took another look. A
careful reading of the Mailman site, https://list.org/, reveal a
surprising amount of good information. Here are the key items.

Latest source release:

https://ftp.gnu.org/gnu/mailman/mailman-2.1.39.tgz

Installation instructions:

https://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/doc/mailman-install.txt

Various documentation:

https://list.org/docs.html

Security statement from Mark Sapiro:

https://wiki.list.org/msapiro

"I am a mailman developer. I am the release manager and close to the
sole maintainer of the Mailman 2.1 branch. Mailman 2.1 is end of life.
Going forward there will only be i18n updates and fixes for significant
bugs and security issues."

That sounds good enough for me.

NOTE: When accessing Mailman's Wiki or the Bazaar version control
service at LaunchPad you may get busy timeouts. Just reload the page.