I should note, too, that Mautic is far more powerful in many ways than MailChimp, and is fully #libre. If you want see an earlier case study on our use of Mautic, see https://www.irrodl.org/index.php/irrodl/article/view/5763/5600 and search for 'CastStudy' - it's a peer-reviewed journal paper we wrote a few years back. Many thanks to @mackiwg for giving me the opportunity to join him and the Foundation way back in 2015 to work on this stuff.