(2023-04-24, 20:44)Manfred Schaefer Wrote: I don't understand.
The paths in which parts are to be searched for can be set or additional paths can be added to the standard paths. For example in MLCAD these paths are defined in the INI file. In LPub3D there is a menu for the search paths.
While it's true that many LDraw programs allow for custom paths, not all do. Additionally, requiring users to do this just so that they can load LDraw files created in the past is not a good user experience. Finally, ignoring all that, suddenly adding a new "standard" LDraw directory and stating that moved-to parts all need to go there is definitely not backwards compatible. It is the very definition of "not backwards compatible".