I've got "1.58" and its actually a mod of some older version. It was before console roms were split out into their own folders. I wish we knew what version it was actually from to collect the matching romset.
The one big feature this mod has is an auto-frameskip that works pretty well. Like Afterburner II looks choppy but the audio and game logic run full speed. And 60 FPS titles like CPS II are still 60 so its a good set-and-forget.