LG G5 devices on AT&T carrier are receiving new firmware OTA update. The update is based on Android 7.0 Nougat, brings version H82020O that installs, June security patch on the device. The H82020O build also brings improvements in the firmware that performs minor tweaking to improve stability.
If you own an AT&T LG G5, what are you waiting for, just go to Settings > About device > System updates. You should have a working WiFi connection to download the update. The H82020O firmware weighs about 109MB so keep your battery well charged to avoid shutting down during the installation process.