Check out Hall for business messaging. Has a Linux, Mac, Windows, iPhone/iPad, Android, & web apps. All free, with unlimited members, groups, integrations, and history. https://hall.com/download-hall/hall-for-linux
Has anyone checked out Hall? It's chat, text, and file-sharing for teams. Free for teams for an unlimited time. But with the added bonus of being able to talk with ANYONE from ANY email address, instead of switching in and out of teams like on Slack. Try it out: hall.com