Retiring Mailman, Spring 2021

IT Services is decommissioning Mailman, which has been used in 2 ways at Sussex:

  1. Send bulk emails to distribution lists
  2. Create an email-based discussion group

We are replacing Mailman with two services that provide most of the same functionality, and in many cases offer new features.

We realise this change will cause some disruption to the way you work, and we hope that the resources on this page will allow you to transition smoothly to the new technologies.

On this page:

Why is ITS decommissioning Mailman?

As the last year has proven, the University depends on a stable, adaptable and future-proof technological foundation. We were able to pivot to online learning so quickly because ITS had been moving towards cloud-first solutions for the last few years.

In order to provide the kind of capabilities that we want to deliver in the future, and in order to provide the level of security that’s expected within our sector, we have examined every piece of hardware and software within our estate. Older systems that can’t meet these demands are being replaced and phased out.

Unfortunately, Mailman is one of these platforms. It is a specialist, focused system that’s designed to do one job, and it does that very well. However, despite our best efforts we haven’t found a way to make it fit within the modern suite of platforms and technologies that we are adopting as we modernise the University’s IT estate. If we want to enhance our security further, and if we want to offer wider features in the future, it must be retired.

Our approach has been to consider the way that Mailman is used, and then find solutions that already exist within the Microsoft suite.

The replacement for Mailman as a distribution list

If you have used Mailman to send bulk emails, perhaps to a school, department or the whole University, then your replacement is a system that already exists within our email system, called Distribution Groups.

If you own a Mailman list of this type, and if you replied to our recent survey, then your list is being turned into a Distribution Group.

You can access Distribution Groups via Outlook Online (, the web-based email client you have probably used before).

Your members won’t notice any change when they receive messages. The message will come from the same address.

How do I email my Distribution Group(s)?

To email your members, just compose an email and put the list address in the To field (or the BCC field, if you don’t want your recipients to be able to see and contact all members of the Group).

You will be able to find your list in the address book if you can’t remember the exact name.

By default, only owners can do this. If somebody else tries to email your group, you will be sent an email asking you to moderate this message. This setting can be easily changed, if you want to allow some senders - for example group-members - to email the list without moderation

How do I find or edit my Distribution Group(s)?

Visit, log in if necessary using your, then click on the cog icon in the top right corner. Click in the search box and type Distribution, then click on the option for Distribution groups.

Here, you can edit lots of settings, and you can add/remove members.

For more details, please see Microsoft’s guide about using Distribution Groups.

Key information for list owners

  • Emails sent to a Distribution Group will appear to come from the sender. If you don’t want your name to appear on the email, please use a role-based account to send the email.
  • Any messages you receive about your Distribution Group will come into your inbox (or, if you used a role-based account to send a message, it will come into that inbox). For example, if you need to moderate a message, you will be notified via your inbox.
  • If you don’t want your members to see a list of all the other members of the Group when they receive your email, add the address to the BCC field instead.
  • If you use Mailchimp to email a Mailman list, you will be able to carry on working in the same way with Distribution Groups. They use the same email address, so you shouldn’t notice any difference.
  • Many old Mailman lists were synchronised with a group of users in the University’s database. The same functionality will be carried over to Distribution Groups, so your mailing list will continue to be synchronised with the database.
  • You can only add members who have a Sussex email address. If you need to add external members, please contact the IT Service Desk.

The Replacement for Mailman as a conversation group

If you have used Mailman to hold conversation threads, then your replacement is mail-enabled Microsoft Teams.

You can continue to use these as email distribution lists, so any member can email the list and everybody will receive the message. The email address of the list will remain the same.

However, if you want to make use of the Microsoft Teams application (which is becoming the standard platform for chat, file sharing and collaboration between staff the University) you can do this too. All members of your list will also be members of the Team when they next open the Microsoft Teams application.

How do I find my inbox for the email address?

In Microsoft Outlook (either the web version at, or Outlook on your computer), there is a list of Groups in the left hand pane, under all your accounts and folders. Scroll down to the Groups section and you will find your new inbox.

From here, you can compose new messages to the group, review messages from other members, or (if you are the owner) change the settings for the list.

How do I use Microsoft Teams?

Teams is quickly becoming one of the core applications used at Sussex. Staff use it every day to chat, call, share files, or collaborate live online. If you used Mailman as a method to have conversations, you will find a new Team within Microsoft Teams with the same name as your old list. You can begin using this right away, or you can continue using the email method explained above. Or you can use both. It’s up to you and your members.

If you are new to Microsoft Teams, you can:

Key information for list owners

  • If your Mailman list had Archiving enabled, your archive will be available in Microsoft Teams, under the Files tab of your new Team
  • Messages that you receive will appear in 2 places: your own inbox (no matter how you access your email, so for example users of Mac Mail will see their messages here) AND the inbox in the Groups section if you use Outlook (either or in Outlook on your computer). You can find Groups in the left hand pane, below your inbox (you may need to scroll down the left hand pane).
  • If you visit your list in the Groups section in Outlook, you will find settings (cog icon) that control how often, and in what form, your receive messages from this list.
  • If you don’t want your members to see a list of all the other members of the Group when they receive your email, add the address to the BCC field instead.

Updated on 27 April 2021