Piper has been updated to support Python 3/Maya 2022. The main caveat for piper was the relative/absolute import statements that are necessary when you import a bunch of modules into a __init__.py. Besides that, take note of divisions where you expect an int, because Python 3 will return a float when dividing. Then there's obviously the print function that any python 2 to 3 converter should take care of, along with range/xrange and a few others.
Moving on to the rigging segment of the blog post, FK controls now include a local control that only moves the driven transform and nothing else. Similar to a butt control that moves only the hips and is parented under the Center of Gravity (CoG) control.
Last but not least, space switching is made easy through a Graphical User Interface (GUI)!
GUI provides regular space switching on controls with space attributes, FK/IK switching on controls with FK/IK attributes (including proxies!), and resetting dynamic pivot transforms. More on dynamic pivots next week probably.
When switching spaces, user has option to turn off/on matching on the translate, rotate, and/or scale channels.