@pitaj Prior to running ./nodebb upgrade I always do apt-get-update apt-get-upgrade so the server is already fully updated.
If there is something else that NodeBB requires then it should be part of the nodebb upgrade command.
It's used behind the scenes by the OAuth code. It's not sending a username or password, it's just the url that kickstarts the OAuth process. It's caught by your app, and shows the "Do you want to authorise NodeBB to use your xyz account?", or a plain login page if no user is logged in.
I see, so at this point it all depends on my implementation of the OAuth server...
The problem was that my server operates entirely in JSON, and doesn't display any kind of page (being pretty raw).
Thanks for the hints though, I'll try to work it out, somehow.