Changes include new pictures, some updated recipes, and some new recipes. In her own words:
https://www.instagram.com/p/B3KWyPzn_6Y/?utm_source=ig_web_button_share_sheet
For one example, the dandanmian recipe was slightly different in the new edition - it included sweet flour sauce in the pork topping and sesame paste in the sauce.
Also a discussion here on HO:
The updated version of Fuchsia Dunlop’s Land of Plenty is remarkable, and well worth getting for owners of the original edition. Layout is more user friendly, pictures are great, ingredient section reflects wider availability these days, and recipes are updated and include 70 new ones. Anyone had a chance to compare old versions of recipes to the updates?