New things to note:
- User accounts: List management via the UI is now done without shared passwords, just sign up here using your email: https://lists.clarkson.edu/accounts/signup/?next=/mailman3/lists/
Any account associated with an email that was already in the moderator/owner list will have the same permissions now.
- Archives: The archive interface is considerably more useful, now similar to a forum interface for your lists. Check your lists' archiving settings if you'd like to make use of the feature or restrict access - your old settings did carry over, but it's worth reviewing now that users can post to the lists from the archive and easily search all contents.
Useful links:
Archives
(List -> Settings -> Archiving)
The archives are now fully indexed and searchable, as well as on an interface with considerably more features. Most notably, you can participate in threads from there now. This + fully indexed content means the archive is akin to a forum for your lists. Please review the archive settings of lists you moderate - ensure they are set to private if you wish to keep record but only accessible to list members. Also keep in mind that the regular posting rules (i.e. members only, members only + approval, etc) still apply to the archives interface, so setting an archive public doesn't mean you are giving the internet free reign over the list.
Note that the default view only shows postings from the last 30 days, click the All threads button on the left side to see everything.
Subscription management
All users can log in and change their personal preferences (either globally or for a specific list), subscribe to new lists or unsubscribe from old lists, view archives of lists they are subscribed to, create new threads, reply to existing threads, vote on entries, save things to favorites, and more. Review the useful links above for some examples.
Viewing a list of which you are not a member:

You are a member:

List owners can now more easily manage members, moderated messages, templates, and settings with the new interface. There are no more shared passwords, each individual has an account and can control everything with a single session. Simply login and select any list for which you are an administrator on the homepage.
Feel free to respond to this thread with questions, or send the link to your list members (https://lists.clarkson.edu/archives/list/mailman3@lists.clarkson.edu/thread/EYIPLJ4VQLW5Q3MFPUI4RUGFCSUW4XJK/)
Gavin Riggi
Linux System Administrator
Office of Information Technology
Clarkson University