AT&T is now rolling out a new software update G950USQU1AQJC for Samsung’s Galaxy S8 devices in the US. The latest patch fixed recently discovered KRACK Wi-Fi security vulnerability.
In addition, the update also includes Android October Security patch with minor bug fixes and general performance improvements. The patch size is around 165-473MB.
Software update G950USQU1AQJC for Galaxy S8 will gradually release to everyone. You can also check manually for updates, go to Settings > About device > System update.
Make sure you have enough charge on your device at least 60% to 70% before downloading the update.