Although it's raining software update for carrier variants in United States. Don't be surprised because it's not Android Oreo, it's Android Nougat. AT&T and Samsung has rolled-out Android 7.1.1 Nougat update to Galaxy J3 2016 SM-J320AU model and that surprises us, not because of timing but due to the fact that the phone was launched in January 2016 and within couple of months will be two years old device.
The Galaxy J3 2016 Nougat update arrives with the August security patch fix update that currently available on the device. The update addresses the BlueBorne security exploit and adds new features like Wi-Fi calling and HD video calling. The kernal number was found to be 3.10.9-12256182 and build number was NMF26X.J320AUCU3BQI5.
Since this is a major update, the software size is of around 1 GB and make sure that you have that space available on the device before going for a download. Also make sure that you are connected to Wi-Fi instead of normal 4G or 3G mobile data connection on your device because that will incur additional data charges on your device if there is no datapack active on your device. You should also ensure that you have charged your device to 50% battery life.
If you have received the update notification on your device, then follow the onscreen isntructions to download the update and it will get installed automatically. You can even force check for the update availability manually by going through Settings > About Device > Software and then tap on Check Now.
Perhaps this would be the last major update that is been roll-out to AT&T variant of Galaxy J3 2016 model. And going by the numbers, new Galaxy J3 2017 will get the Android Oreo update, nearly same time as that of this one, including the carrier variants too.
A couple of days back, ZTE Maven 2 on AT&T too got the same 7.1.1 Nougat update.