Moving from version 4.0 to 4.1, you will also need:
- update the Node.js server (if remote, i.e. as a cloud service).
- regenerate the HTML quizzes produced with QF, if they use the saving mode on the server (local or remote).
This is necessary as the server-side APIs have been updated and now all APIs require authentication, and in the case of an "anonymous" quiz will be used a fake user named "anonymous".