Samsung's new One UI based on Android 9 Pie will be released sometime next year but apparently, that includes only the latest Galaxy S9, S9+, and Note 9 devices. According to a Samsung representative at the ongoing SDC 2018, the Galaxy S8, S8+, and the Note 8 will not be getting the new One UI user experience. However, it is not clear at this stage whether these devices will be getting the Android 9 Pie update separately or not.
https://www.notebookcheck.net/Samsung-s-One-UI-will-not-make-it-to-the-Galaxy-S8-S8-Plus-and-Note-8.357911.0.html
zzz typical samsung dev moves, really fast to abandon older devices
It's not gonna be a big deal in any means
This UI looks like s***, I am so happy that the S8 is not receiving it, but I hope it gets the Android Pie