Ahead of LG G5, the V10 smartphone on T-Mobile gets the Android 6.0 Marshmallow update officially. It turned out to be a special day as lot many devices including the Nexus 5X and Nexus 6P which got the update in October for the International version, carrier variants are getting the update today. Moreover both Galaxy S6 and Galaxy S6 Edge too on T-Mobile are seeding the update.
How to Update
The update is available for download via Over the Air [OTA] and if you don't have a WiFi nearby then connect your phone to PC using the USB cable and install the LG Bridge app, you can download it from here.
You might have received the update notification on your device. If you haven't received they head over to Settings > About Phone and then System Updates. Now pull down the update from the server by tapping on Download.