Yesterday Samsung finally started rolling out the Android 8.0 Oreo update to Galaxy Note8 units sold unlocked in the US, and today it’s done the same for the unlocked Galaxy S8 and S8+.
The new software arrives as a 1.3GB download, so maybe grab it via Wi-Fi. After applying it your S8 will be on build number G950U1UEU2CRB9, while the S8+ gets G955U1UEU2CRB9. Both will be running Samsung Experience 9.0 of course. The security patch level will be March 1, 2018.
There are many new things in this update aside from the change in Android version. These have been detailed by the Korean company back in February, in preparation of the subsequent rollouts. You can also check out the Source links below, which contain the official Samsung changelog for both models.