I found a GitHub repository who built tar.gz release with a sourcecode that ca be run on a ARMv7, but I've the needs to run in a docker container.
This repository contains a docker-compose.yml to run a mattermost stack onto a raspberry pi
Or, you can find a bunch of script to build docker image based on https://github.com/mattermost/mattermost-server and build within GitHub Actions.
Frequently, I create new release and new docker image, so if I'm late, feel free to open a Pull Request.
You just have to update ’dependabot/go.mod’ and ’.github/workflows/release.yml’
Original repository for source code : https://github.com/SmartHoneybee/ubiquitous-memory