Please note, Plesk has supported the version of Mailman provided by OS vendor by default.
The Mailman 3 is shipped by default on Ubuntu 18 and Debian 10.
Please keep voting if this request is still actual for you.
An error occurred while saving the commentkasper commented
I'm still wainting for mailman 3. please add it as soon as possible because dmarc spf etc. is really important today.... mailman 2 gets more and more unusable