Feel free to open a support ticket so we can take a closer look and determine why the newer version is not installing on your system. You can post the ticket number here so we can update this thread with the outcome.
For everyone else I'd like to let you know that mailman 2.1.18 was released. We are in the process of upgrading mailman in both 11.44 and 11.42. I don't have an ETA on release other than "soon."
Thanks, Kenneth! Not sure if you saw my previous post, but there was a problem with 2.1.18 and a fix was released, which is being distributed as 2.1.18-1. Glad that you guys have the update on your radar! Thanks for your work on this!
To update, it was determined the system was not actually using cPanel version 11.42. It was stuck on an older version of cPanel due to some package update errors. The new version of Mailman is now installed after successfully updating cPanel.
You guys are awesome. Thanks for the help. One of the problems with cPanel, is that it takes care of so much, that when a problem does arise, I'm not familiar enough with it to know when it's a problem.
Note that right now, cPanel 11.44 is in the EDGE and CURRENT update tiers. RELEASE and STABLE are still 11.42. You can always see which version is in each tier by viewing this page:
You can select your update tier in Home » Server Configuration » Update Preferences. Note that cPanel will not allow you to downgrade to a previous version, even if you select a tier that contains the previous version.
Mailman version 2.1.18-1 is now available in cPanel version 11.42.1.17. This version is already available in the "Release" build tier, and is scheduled for the "Stable" build tier next week.