Mailman 3 Release Notes

GNU Mailman 3 is actually a suite of 5 subprojects:

• Mailman Core - the core delivery engine which accepts messages, providers moderation and processing of the messages, and delivers messages to mailing list member recipients. It exposes its functionality to other components over a private, administrative REST API.

• Postorius - A new Django-based web user interface for end users and list administrators.

• HyperKitty - A new Django-based web archiver.

• mailman.client - The official Python 2 and 3 bindings to the administrative REST API. Used by Postorius and HyperKitty, this provides a convenient, object-based API for programmatic access to the Core.

• mailman-bundler - A convenient package for building out the entire Mailman suite.

The Core is required. Postorius and HyperKitty are awesome, and highly recommended, but you could of course roll your own web ui and archiver. mailman.client is useful, but you could always program directly against the REST API. mailman-bundler is also useful, but you could build out your own suite of these tools.

Compatibility chart

Mailman 3 is architected and released quite differently than Mailman 2.1. It is important to know which versions of these 5 components are compatible with each other. Our current thinking is that we'll coordinate releases on major version number boundaries, e.g. 3.0, 3.1, etc. but that each component will have its own patch release schedule, as appropriate for that project.

The crucial point of interoperability is the REST API, which is versioned. In Mailman Core 3.0, the API version is also 3.0. Our intent is that for any changes which are backward compatible, such as adding new end points or methods, we don't need to rev the API version. Backward incompatible changes to the API, e.g. removing an API or changing attributes of a resource, will require a version bump of the API. It's also possible that tools such as Postorius may be compatible with different versions of the API.

This chart describes the versions of the components which are officially defined as compatible.

Known Issues