The update has been made available on two Korean Telecoms out of the three, that are SKT and LG U+ (F240S and F240L models). While the third, KTF will be getting the KitKat treatment, only till end of this March month. The update has been provided over the air, i.e., it is an OTA update that would upgrade your LG Optimus G Pro to the latest version of Android. Also the update is said to increase the speed of the device, and performance boost.
The update also improves the messaging capabilities with the integration of the Hangouts app. Also make some changes in the User interface, like you can change the color of the notification bar, and also the update improves the RAM management of the device.
With the update rolling out in Korea, the update for the international LG Optimus G Pro, is not that far away. LG has already updated the LG G2, so the next would be the Optimus G Pro if we go by the hierarchy.