I am using the default Mailman version with CentOS 7 and Plesk Onyx, which is Mailman 2.1.15. yum update doesn't show a later version. The current version of Mailman 2.1.x is 2.1.24, and there have been many changes since 2.1.15.
I would like to use at least Mailman 2.1.18 to take advantage of...