Kirby's Extra Epic Yarn will come to Nintendo 3DS in 2019, but it seems that the title could work only in the "New" range of the console, making it exclusive to these models (New Nintendo 3DS, New Nintendo 3DS XL, New Nintendo 2DS XL).
In the game's official website it is indicated that it is a game that only works in the "New" models.
This detail was not indicated in the Nintendo Direct where the game was presented or in the press releases on the title, so we still can not be completely sure if it is some kind of error on the web or if, indeed, it will be compatible only with these models of the console.
New Nintendo 3DS has been sold since 2014 and the New Nintendo 2DS XL model since 2017.