Curious about your setup: did you use their recommended install method or a Docker image? And, more importantly, did you encounter any serious issues during that time? I'm considering replacing Slack with Zulip and wondering what could possibly go wrong.
Not your parent but I did setup Zulip at two orgs now. Just used the official method. Never had a problem. Zulip has a very good Puppet setup that works very well.
Ubuntu Server, used their standard install instructions, no docker. So far all their upgrades went without any problems at all, including major version bumps.
As for running the server, I cannot recall any bigger problem I had, Zulip runs in our org for more than 5 years.
