The update includes the new Knock Code screen unlocking feature that LG has been heavily promoting since last month (the feature is already available on newer handsets, starting with the LG G Pro 2). What the update doesn’t seem to include is support for 4K video. But maybe this will be available when the KitKat update arrives on the international version of the G Flex? We can’t know for sure, but we’ll certainly keep you posted.
The G Flex was released by LG in November last year as its first smartphone to feature a curved, flexible display. The handset can be purchased in many markets around the world, including in the US - where we're hoping to see it getting KitKat soon.
source: LG (in Korean, automatic translation not available)