Not to be confused with the 1.0 Stages category, this category should contain stage versions that are intended to be used with M.U.G.E.N 1.0 and may not function properly in earlier versions of the M.U.G.E.N engine, if at all, but still function in later versions; outside of crashing the engine, unintentional functionality can extend to the use of localcoords and other features introduced in M.U.G.E.N 1.0 that are naturally not parsed in earlier versions of the engine, so while the stage may load, there's no guarantee it will display or perform correctly.