It’s either by design (feature not a bug) or zero testing.

Either way, really poor form to be honest (I’ve had several decades experience as a programmer so I know what I’m talking about).

At the very least some backwards compatibility should be present. For example Python 2 should be an option in Poser 12 and Poser 13 move to Python 3 exclusively. Things should be deprecated for a while before being removed.

Hopefully Bondware will fix the shader issues and then Snarlys update will have a chance at working.