Ignore me. The docs answer my question:
Run grunt to start up NodeBB and watch for code changes.
What would be the best way upgrade forum V0.6.0 to the lates?
You should be able to get the latest code and run
./nodebb upgrade. Make sure you make a backup of your database.
Wow, v0.6.0! That's going to be a fun one.
What I'd recommend is deploying a copy of your forum to a new environment purely to run the upgrade on it, then you can handle any errors that come up, and we can guide you through the process.
Now, of course, ideally, there won't be any errors, but v0.6.0 was a long time ago....