AT&T has released a new software update AAO750 for BlackBerry KeyOne in the US. The new update comes with Android September security patch which addresses a total of 81 Common Vulnerabilities and Exposures (CVE) in the open-source Android OS.
The firmware update also includes device stability improvements, bug fixes and further improvements for performance. The device is running on Android 7.1 Nougat.
The OTA software update build AAO750 for BlackBerry KeyOne will gradually roll out to everyone. However, you can also check manually for the updates, go to Settings > About device > System update.