Mattermost is open source, but the licensing is complex and full of bullshit. It is not a community driven project. Once you have installed the self hosted solu

Mattermost is open source, but the licensing is complex and full of bullshit. It is not a community driven project. Once you have installed the self hosted solution, you get a user interface that asks you to upgrade to the enterprise edition in every corner and menu. A self hosted version is better than nothing though.