I'm migrating my server from Ubuntu 14.04 to 18.04 on a somewhat better hardware platform. I'm using Virtualmin Pro 6.03 and Mailman 2.1. Overall the strategy of backup from the old server and restore to the new one has worked well but there's an issue with mailman 2.1. On the old system if I log in as admin and select a server where there are mailman lists I am able to then look under services and see an entry for mailing lists. Clicking on these leads to the usual mailman login and admin interface. But on the new virtualmin install, still with 6.03 Pro, the mailing list entry is absent under the services entry. Moreover the previous Virtualmin theme seems to be absent so I am not able to search for and can not find the mailman login or admin features.
Some of my clients do nothing but mailing lists so this has to work. Please let me know where I can look for the mailman interface or what better information I can provide.