I don’t think they do, do you have any source? A slim phone is expected next year, while foldable iPhones seem definitely to be in development, but rumors do not point to next year.
https://www.macrumors.com/2024/06/03/foldable-iphone-unlikel...
https://www.macrumors.com/2024/06/03/foldable-iphone-unlikel...