Samsung Galaxy Note 8 unlocked units started to receive Android Oreo update weeks back and the units on T-Mobile started to receive the update. T-Mobile product manager, Des, confirms on Twitter saying that Samsung Galaxy Note 8 Android Oreo update has been approved and the update will start to hit devices starting April 1, Sunday.
— Des (@askdes) March 30, 2018
Android 8.0 update brings Samsung Experience 9.0 to the mix, which brings all the features available in Android Oreo. Check the update manually, Head to the Settings and tap Software update.