@pluralistic #NixOS has modules for #Sympa and #mlmmj.

https://search.nixos.org/options?channel=22.11&from=0&size=50&sort=relevance&type=packages&query=sympa++%7C+mlmmj

#mlmmj 1.4.0 alpha1 is available here: https://codeberg.org/mlmmj/mlmmj/releases

This is a very early release which main goal is to make people know that:
1/ yes mlmmj is not dead
2/ lots of code modernization happened and probably portability issue has been introduced (mainly tested on #freebsd)

Please test and report issues!
DO NOT USE IN PRODUCTION!!!

Bon bah je crois bien que mon serveur de listes de diffusion est opérationnel !
Merci #mlmmj et #freebsd pour la facilité de la mise en place :)