LG G Pad 8.3 Google edition is getting the Lollipop OTA update today! Some users already have their updates, which is why most of us can now get our own manual update from the ZIP file linked below.
In order to flash the manual update, your device will have to be back on stock Android (in case you changed something software-wise) and use ADB manual flash. Some modifications made do the stock system, such as root, are going to interfere and block your manual update too, so beware. Even after you update there may be a few bugs to sort out, considering most updated phones so far had little Lollipop-related issues.