Quote - The onus of not breaking older plugins is on the base app. Here's what I mean:
For example, you expose a Geometry object through an API. In the first version of FAST, subdivision is not supported, so the Geometry object doesn't have a SubdivisionLevel property.

I agree wholeheartedly, but it seems as if Daz seems to be taking slightly different take on it, in that they seem to break backward compatibility from the old to the new API whenever it suits them and the plugin writers can either do what they have to do to compensate or their plugin can stay broken, Daz doesn't appear to care much either way, at least on the surface of things.

This is probably one of the biggest reasons I've stayed away from Daz studio, I don't want to be investing a bunch of money in plugins only to find out that they are not supported by a new version, even worse to find out that the developer has decided to double,triple or quadruple his price with no upgraded pricing available for the new version of his plugin to the new version of D|S.

Being that dependent on that many different parties, and being subject to the whims of so many different developers - well, just not my cup of tea. 

-Never fear, RenderDog is near!  Oh wait, is that a chew toy?  Yup. ok, nevermind.. go back to fearing...