It never really worked, except on the most basic of command line tools (and, in theory) some very lucky apps that used OS3.9 ReAction, but I never saw that work). These tools generally were easily recompiled anyway.

And then compatibility that mostly stopped when OS4 coders mosttly started to link dynamically to an OS4 shared library that couldn't be wrapped. I forget the name - probably newlib.library.

As a pin to deflate some very large egos, it was excellent though. In its day.