Although the carrier's support page for the Note 8 hasn't been amended to reflect the changes, screenshots of the push notification for the patch were spotted on Reddit.
The changelog only mentions the inclusion of the Android Security patch for September 2018, but users also report that the software upgrade contains Super Slow-Mo video capture and AR emojis. There might be other changes on board as well, so please let us know if you spot anything new in the comments!
The update is available OTA, but it might need some time to reach all compatible devices. You can check for it manually by going to Settings > About Device > Software Updates. As always, make sure that your phone is sufficiently charged and connected to a Wi-Fi network before proceeding with the patch.