muvgc

Hi, just have a question regarding the firmware to be able to use pkhex successfully. Im looking to buy a 3ds with the right firmware which is why im asking this. Ive seen one with the firmware version 6.3.0-12E, is this version compatable with pkhex? Or is there a way to update it to the correct firmware without getting the latest firmware which doesnt work? If this firmware wont work what firmware should i be looking to get on a 3ds? Thanks in advance