Samsung has released a new software update for its unlocked Galaxy Note 9 device in the US. It is the second update this week. According to the changelog, the update includes September 2018 security patch.
The software version of this update is N960U1UES1ARH6, and the size of the update is 94.44MB. You can check for the update manually by heading into the Setting > Software update.
Last month, Samsung released an update for the unlocked Note 9, which adds another timeframe (0.2 seconds) to record Super Slow-Mo video. It was also on August 2018 security patch.