hi elias
do you mean that we can install the latest docker and then it will upgrade our existing 3.4 container?
i tried that and it didn't work.
when we launched our existing container, it is still 3.4.
we don't want to lose our contents.
we followed the instructions here
https://docs.mattermost.com/install/docker-local-machine.html#ubuntu
we got this error:
docker: Error response from daemon: Conflict. The container name "/mattermost-preview" is already in use by container 3c9a868d7433991cfa9f9b3d0a9dd6314c921759e8451026c80aa3aac7a02e28. You have to remove (or rename) that container to be able to reuse that name..
when running this
docker run --name mattermost-preview -d --publish 8065:8065 mattermost/mattermost-preview
thank you