The new firmware carries version number V405UA20d and weighs around 1.5GB in size. It brings Android Pie niceties, new UI and new navigation to the V40 ThinQ, in addition to bumping up the Android security patch level on the phone to April 1, 2019.
It’s unclear why an update seeding in June only has the April patch – it could be that LG is running behind schedule or AT&T taking too long to approve the release as US carriers often do. Hopefully this gets rectified in a subsequent update soon.
Either way, this update is rolling out over-the-air and could take at least a week or two to reach all the V40 ThinQ units on AT&T’s network. If you can’t wait for the update notification to pop-up on your device, you can try pulling the new firmware manually by heading over to Settings > About Phone > Software updates menu.