@mark-coniglio hi Mark. At this time I am not aware of any regression with the mentions plugin, which would usually point to some sort of configuration error.
Do you see any errors on the client side, in the browser dev tools?
You'll need to install manually, it's been months since I've heard from Sam, so idk when the PR will be added.
npm install git+https://github.com/yariplus/nodebb-theme-persona.git#creepr
If you just want to add subcategories to your own theme, the needed changes are in my last commit.
