The AT&T Samsung Galaxy S8 and Galaxy S8+ are receiving a new software update right now. If you own either of these devices, then you should have got the update notification. This is only for the AT&T locked Galaxy S8/S8+.
The update is available over-the-air and brings along some security enhancements and bug fixes. The December Android security patch is installed, and also included is the BlueBorne vulnerability fix. Build number for this update is G950USQS2BQL1 for the Galaxy S8 and G955USQS2BQL1 for the Galaxy S8+.
There aren’t any new changes apart from that, but it is certainly an update that you must install as soon as your device gets it. It weighs around 130MB in size and is based on Android Nougat.
Samsung hasn’t yet released the Android 8.0 Oreo update for either of these devices. The beta program is going strong, with the fourth beta recently released, but an official release is still at least a few weeks away.