UPDATE 26/3/20: Nintendo has rushed out a small update to Animal Crossing: New Horizons which “fixes a serious bug affecting game balance”.
That’s the only change listed in Nintendo’s patch notes – and it seems to refer to the item cloning exploit described below.
The exploit’s removal was inevitable – and this patch will likely propagate fast as all players must be on the same version number to play online together. Were you naughty and used it while you still could?
ORIGINAL STORY 23/3/20: Unscrupulous (or go-gettingly enterprising, depending on your perspective) Animal Crossing: New Horizons players have a crafty new tool at their disposal in their quest for financial superiority, arriving in the form of a freshly discovered item duplication exploit, enabling them to rack up hundreds of thousands of Bells with minimal effort if they so choose.