Although Apple has previously said that this controversial feature would not be pushed to its post-iPhone 7 handsets, it seems that the Cupertino-based giant has decided to add speed throttling for the iPhone 8, iPhone 8 Plus, and iPhone X in the iOS 12.1 update after all.
https://www.notebookcheck.net/Apple-s-iPhone-X-gets-speed-throttling.354736.0.html