Do you mean the installed package?
rpm -qa *roundcube* | sort
or something else like the database?
The note is just about a configuration event signal-event nethserver-roundcubemail-next-update (not a “command” by itself) that you usually do not need to run unless you change some related setting from command line or something related is not working and you decide to run that event to re-run / reapply some actions.
The other notes on github were for QA testing the package, I consider there are some tips and precautions that still could apply but other bits are outdated. So not a guide to follow to the letter.