In September 2017 Nintendo took long-time character lore and told gamers that Mario no longer worked as a plumber. The company seems to have had a change of heart and restored Mario's occupation to a plumber.
Nintendo updated his official Japanese bio to reflect the change.
Worked As A Plumber
In Nintendo's previous change to Mario's official biography read that he once "worked as a plumber." Now Mario's current bio reads that his occupation is a plumber. A rough translation reveals that Mario is a plumber.
Mario's former profile acknowledges all of his adventures throughout Nintendo's vast library of games but removes his occupation.
"All around sporty, whether it's tennis or baseball, soccer or car racing, he [Mario] does everything cool. As a matter of fact, he also seems to have worked as a plumber a long time ago..." said the former update to his profile.
One of Mario's former occupations also includes being a doctor at one point. Creator Shigeru Miyamoto acknowledged that he wasn't always a plumber. He was only made a plumber once Luigi was added to the game for 1983's Mario Bros.
Even during his first real appearance in Donkey Kong, Mario wasn't even Mario yet, he was just Jumpman. Miyamoto called him a carpenter during that original game.
His new bio directly addresses that he is a plumber.
"His occupation is plumber. However, his activities don't stop there. He loves Princess Peach. If she is ever in trouble, he will go to help her no matter what [he will drop whatever he is doing if she needs help; literally "no matter what time it is, he will go to help her"]" says Mario's now updated biography.
Something that is learned through the bio is that Mario and Luigi are actually twin brothers.
The change to Mario's biography comes at a weird time. In Super Mario Odyssey, Bowser refers to the now plumber as "plumber boy" during a stage of the video game. If he means this as an insult, why did Nintendo change his occupation back to a plumber?
Bowser's insult has become a meme.
Maybe everyone has just been reading too much into Nintendo's biography for Mario.
like, a Nintendo website ended his description with "we hear he was even a plumber once" or something, which is obviously a joke about just how many things Mario has done over the years, but for some reason everyone flipped their shit over it — nepetaquest 2018: the revival (@DudewitdaK) March 6, 2018
Nintendo previously addressed Mario's belly button.