When Mario Kart 8 was released on the Wii U competitive players were quick to seek out tactics which would give them an advantage over their rivals, and one such sneaky trick was "fire hopping", which allowed players to shave seconds off each lap.
Nintendo didn't address this trick with a patch, forcing many to use it when playing online and trying to top leaderboards. However, it would seem that the company has now taken action with Mario Kart 8 Deluxe, as fire hopping no longer works - in fact, it actually slows you down, according to GameXplain:
Why Nintendo has waited until now to patch this trick is anyone's guess; it could (and possibly should) have patched it back on the Wii U. Even so, it's good to see the playing field has been levelled again - until someone else finds another exploit, of course.