Mailing lists/Mailman3 migration

In 2021 we upgraded the mailing list software to Mailman 3, which is a full rewrite, fixing lots of long standing issues, especially around security. A short list of improvements:

  • One user account (no more monthly password reminder emails or list passwords)
  • Ability to search through archives
  • Posting through a web interface
  • A web interface that doesn't look like its from the early 2000s

For the most part, if you just send and receive mail from the list, nothing dramatic will change.

We migrated mailing lists in May 2021. They were migrated in batches, starting with lists with no archives, and then going by size of archive and # of subscribers. Very big/old lists (wikimedia-l, wikitech-l, etc.) went last. We sent a notification to the list admins when we started migrating the list and once it was finished.

Action items for list administrators


We will need help from list admins to make this go smoothly.

  • To recap, you no longer need to log in with a special admin user. Just sign up for an account using the email address that was subscribed to the list you administer. The system will automatically give you administrator rights.
  • If your list is obsolete or should be archived, please add "[OBSOLETE]" or "[ARCHIVED]" to the list description and we'll take care of the rest (there is no distinction between the two)
  • Please update your list description to indicate who the list admins are (either usernames, email addresses, etc.)
  • If you'd like to volunteer your list to go early, let us know.
  • On the other hand, if you think your list needs special handling and should go later, let us know as well.
  • It is our intention to have all mailing lists be publicly listed, please let us know if you have a reason that the existence of your list should be kept private.
  • If you've lost track of all the lists you're responsible for, we can look it up for you :)
  • The canonical URL of your mailing list will change. If you link to your mailing list in help pages, templates, etc. You should update it after migration. For example <> will change to <> (we expect to provide redirects).
  • For public archives, we will ensure that archive links will not break. For private lists, we do not intend to support old archive URLs - if this is a big issue for you, please let us know.
  • Custom HTML templates will not be migrated over. Please check that the relevant content on your listinfo page is in the "info" field, not in the HTML template.
  • If you would like to adjust the settings of your list, please file a task in Phabricator.

After your list has been migrated


In Mailman3 customizing the footer and other email messages sent out are called "templates". You can edit them by visiting If you had customized a template in the past, please review its contents as the migration script may have not converted everything properly.

The Mailman3 interface will not show you the default value of the templates. You can see the defaults in the operations/puppet Git repository. It will soon be possible to translate them.

Review bans


In Mailman2 it was possible to ban everyone (.*@.*) and then manually subscribe the people who should be on the list to cut down on spam subscription attempts. This is no longer possible in Mailman3, as the ban list will trump everything else. If an address is banned, their message will be silently discarded, regardless of any other options.

Test installation


A test installation was available at <>, it has since been deleted.



We're taking the opportunity to clean up some things before migrating:

  • Disabling pre-2007 legacy and aliases
  • Mass unsubscribing hard bouncing emails



Important announcements will be sent to the listadmins@ mailing list. All current list admins have been subscribed to this list, we ask that you not unsubscribe.

If you have questions/concerns, you can also reach out to Legoktm and/or Ladsgroup by email or on IRC in #wikimedia-tech.



For tracking the work see T280322.