LG Optimus 4X HD is officially released by Korean’s company on June 2012 with Android 4.0 Ice Cream Sandwich out of box. It is a delay in releasing Jelly Bean update to Optimus 4X HD as in LG had confirmed the Jelly Bean update is nearly ready and to be released in February.
For those who bored of waiting for the official Jelly Bean update on your device, there is a leaked firmware that claimed to be Android 4.1.2 update for Optimus 4X HD. The leaked firmware included all the Android 4.1.2 features such as Google Now, enhanced notification bar, Project Butter, improved stability.
You may head over to XDA thread for the download link of this leaked firmware. Please bear in mind the risk of bricking your device if you have modified your phone incorrectly.