Hi Michel, thanks for the heads up! It looks like there have been some updates to the WidgetKit API since I first wrote this tutorial (I wrote it while WidgetKit was still in beta). After some updates to CustomEmojiWidget.swift and RandomEmojiWidget.swift, I was able to build and run the same project. I uploaded this update version to GitHub: https://github.com/apatronl/Emojibook/tree/master/Part%203. Hope this helps!