Release notes

Mailu 1.5 - 2017-11-05

It has been two years since this project started, one year since it was renamed to Mailu and took a more serious path toward building a proper email server distribution. The experience has been extremely interesting and we as contributors should be quite proud of what was accomplished in that time.

Mailu started as a random project of administration interface for Postfix, it is now running thousands of mail servers, has reached over half a million pulls on Docker hub and contributions from very different and frankly interesting people.

Version 1.5 is about bringing the features that were intended for the late version 2.0. It includes many new concepts like:

  • alternative domains, a way to configure a domain that is semantically equivalent to another;
  • domain relays, a way to relay emails to a separate server;
  • authentication tokens, a way to let users generate passwords for their various clients and restrict authentication per IP address.

The release also includes some structural changes to the project. Nginx is now the main frontend container and terminates all connections, performing TLS and authentication directly. Letsencrypt support is now more complete, with various TLS “flavors” for all kinds of setup.

Finally, a big change about how versions are managed: the stable branch will be deprecated with the end of branch 1.4. Mailu will now only publish branches per version, as any version jump requires manual updates anyway. This will avoid confusion about which branch is currently considered the stable one. End of support for branches will happen after 2 version changes (e.g. end of support for branch 1.4 will happen when branch 1.6 is released). Finally, intermediary versions backporting some important features will be branched as subversions first (branch 1.5.1 for instance), then merge in the branch version once enough testing has happened.

More details about the changes are available in the changelog, and this release will be followed by a short-term upgrade including some more features and bug fixes.

If you are upgrading, please go through the setup guide and download the latest docker-compose.yml and .env, then update them with your sepcific settings, because more than 50% of these templates was rewritten. You should then be able to pull and start your new e-mail stack with no issue, simply remove orphaned container, since some were renamed and others were removed (e.g. rmilter):

docker-compose pull
docker-compose up -d --remove-orphans

If you experience problems when upgrading, feel free to post issues and contact us on our chat channel for emergency support.

Regarding statistics, Mailu has gone from “no tracker at all” to a tracker that we find is designed to preserve privacy and security as much as possible. Your admin container will now perform DNS requests for a domain that we hold, including information about your “instance id” (a unique and random string) and Mailu version. If your mail server performs direct DNS queries instead of going through a DNS recursor, you might want to opt-out of statistics if you would prefer the server IP address not be included anywhere (we do not log it, but our hosting provider might). This can be accomplished in the .env file directly.

Mailu 1.3 - 2016-11-06

First a warning as TL;DR. Following the project rename, please read the migration guide carefully if you were already running Freeposte.

Renaming the project was a critical step in its life and we certainly hope that it will help gain even more traction and collaborate every day to add new features and improve Mailu.

This new release introduces mostly bugfixes and a couple of enhancements. It was however the most complicated to prepare and publish because we had to deal for the first time with multiple active contributors, sometimes diverging points of view, a solid user base that would prefer their production not break, and some major upstream issues.

The release itself was delayed a month, partly due to these changes, partly due to upstream issues. One of them for instance, a bug in Dovecot, took us a couple of long nights debugging low-level memory management code in Dovecot in order to fix the vacation message in Mailu! This lead to humble contributions to Dovecot and Alpine Linux and we are still proud to be contributing to a larger software environment.

Among the major changes that we introduced, Rainloop is now officially supported as a Webmail and we are open to contributions to add even more alternatives to the next release.

Also, Mailu admin interface now has built-in internationalization and we will initiate a localization campaign to add at least French and German to the list of supported languages. Please contact us if you would like to contribute another translation.

Finally, we hardened Postfix configuration both for security reasons (preventing address usurpation upon existing SPF) and to prevent spam. We found that the already effective antispam filter now blocks more that 99% of junk messages on our test servers.

A more detailed list of changes is available in the project changelog.

Please read the Setup Guide if you plan on setting up a new mail server. Mailu is free software, you are more than welcome to report issues, ask for features or enhancements, or contribute your own modifications! 1.2 - 2016-08-28

The past few weeks have been very productive thanks to multiple contributors and reporters. A hundred commits later, release 1.2 is ready.

Most changes in the release are security-related: we eventually added CSRF checks, applied most security best practices including TLS hardening based on the great documentation by BetterCrypto, and started a discussion about how the mail server stack should be secure-by-default while maintaining as many features as possible.

Additional great change is the new ability to declare catch-all aliases and wildcard aliases in general.

When creating an alias, one may now enable the “SQL LIKE” syntax then use standard SQL wildcards % and _ to specify matches for a given alias. For instance :

  • %@domain.tld will match any uncatched email sent to that domain (catch-all)
  • support-%@domain.tld will match any email sent to an address starting with support-
  • _@domain.tld will match any email sent to a one-character address
  • co_tact@domain.tld will match both contact@domain.tld and comtact@domain.tld along will all other combinations to make up for any usual typing mistake.

Finally, the update process changed with 1.2: you do not have to manually setup an installed branch anymore. Instead, you may simply use the default docker-compose.yml file and the :latest tag that will now point to the latest stable version. Those who know what they are doing and still want to use continuous builds from the Git repository may switch to the :testing Docker images.

A more detailed list of changes is available in the project changelog.

Please read the Setup Guide if you plan on setting up a new mail server. is free software, you are more than welcome to report issues, ask for features or enhancements, or contribute your own modifications! 1.1 - 2016-07-31

When we started the adventure back in December, we weren’t quite sure the project would lead to anything but a bunch of scripts to manage our mail server at TeDomum.

About 6 month later, we have got word from a dozen individuals and half a dozen nonprofits that have started setting up or are using it for production emails. All mailboxes at TeDomum have been running on top of for the past 5 months and happily received thousands of emails.

Release 1.0 was definitely not ready for production: the anti-spam services were unstable, lots of junk messages still got through, there was still no support for outgoing DKIM and thus no way to properly setup DMARC. These have been addressed and we are really enthusiastic about releasing 1.1 and expecting some feedback and contributions.

Please read the Setup Guide if you plan on setting up a new mail server. is free software, you are more than welcome to report issues, ask for features or enhancements, or even contribute your own modifications!