I work in consultancy, and the client I currently work for has us working on-premise using air-gapped computers. No internet, only intranet, meant finding new w

I work in consultancy, and the client I currently work for has us working on-premise using air-gapped computers. No internet, only intranet, meant finding new ways to communicate. So far Mattermost works well. We have it integrated with Jenkins, Stash etc. and do the typical "chat-ops" things.