I've already tried to go straight from 0.7.3 -> 0.9.0 with success. Plugin support hasn't caught up yet though.
@pichalite , I'm using a 2nd instance of nodebb, with a 2nd mongodb instance. I first upgraded my plugins to the latest, ran ./nodebb upgrade while on 0.7.3
git checkout v0.8.x
git pull (just in case)
running in dev mode just crashes and relaunches when hitting the categories page. When I first installed the forum, I was using v0.8.0 and switched to v.7.x since the plugin support wasn't updated yet.
I am using the Vanilla theme and it upgraded to 4.0.8 after switching to v0.8.2