I'm running the most recent version, from 1/3/19 (I believe, I can dig into the logs to check for version numbers).
I haven't tried changing libraries, but then again, I'm not completely sure how... I just click "Connect" and "Content Server" and it all springs up.
Edit: The server is running from this image:
https://hub.docker.com/r/linuxserver/calibre-web/