You probably want to add a notch or something that makes it impossible to put the "new" carts into the "old" slots; like they did for DS/3DS: http://i.imgur.co

You probably want to add a notch or something that makes it impossible to put the "new" carts into the "old" slots; like they did for DS/3DS: http://i.imgur.com/OQLR0xM.jpg http://i.imgur.com/OQLR0xM.jpg