> it would be true to form that they would be making it incompatible... just not on purpose.

"FrankenMUI was intentional made incompatible to not support porting stuff from AmigaOS to MorphOS. So from day one there was no will to keep FrankenMUI kompatible for multi platform coding on AmigaOS4 side."
Source: geit in comment 35

> they way they see it, MUI4 on OS4 is now *the* MUI4, and it's now MorphOS that is incompatible.

They released their MUI4 also for OS3. Maybe the MorphOS team should release MUI5 for OS3 as well :-)