Please see https://github.com/NodeBB/NodeBB/issues/3573
If you have a custom theme, you should switch to using cache-buster in your header.tpl
psychobunny created this issue in NodeBB/NodeBB
Update cache buster when switching themes
@Enrique the main problem you seem to be having is that you are not aware that there is a frontend and a backend to NodeBB. You have to wire up the controls from the ACP and make a call to the backend (via websocket, for example), and then you can call server side libraries.