Version 1.8 with CPU Core improvements and maximum speed on DSi and above. Special DS-LITE version included if you want to try this on older hardware - but be warned, the compatibility is VERY low on the DS-LITE version so only try it with small games (Asteroids, Joust, Centipede, Meteor Shower, Moon Cresta, etc).
Otherwise stick to the normal A7800DS.NDS file for maximum compatibility and speed on the DSi or better hardware.