Update to VPython 7.2.0.
You can get the latest version this way: pip install vpython --upgrade
Or if using Anaconda, conda update -c vpython vpython
Problems reported by Adam Hall associated with the interaction of axis and up (to maintain them perpendicular to each other) have now been fixed. Although this is a bug fix, it's possible that some program relied on the bugs, so we've upped the version from 7.1 to 7.2, just to alert everyone to a possible issue.
Thanks to Matt Craig for building the 7.2.0 installers.
Bruce