Sony has already confirmed that some of its smartphones, including the Xperia ZL, will receive the Android 4.4 KitKat upgrade next year.However, the Xperia ZL will first be upgraded to Android 4.3 Jelly Bean, as the smartphone now ships with a previous version of the platform.
Other Sony handsets such as the Xperia Z1 and Z Ultra will be upgraded directly to Android 4.4 KitKat in January 2014, but no exact release date has been unveiled yet.
Anyway, it looks like an official Android 4.3 Jelly Bean update for Sony Xperia ZL has just appeared in Asia and the first screenshots indicate that the smartphone's UI has undergone important visual changes.
The Xperia ZL's UI is now white with black writings, exactly like the Xperia Z1's UI. Aside from that, there's no telling what changes will be added to the smartphone after the upgrade.
According to XperiaGuide, Android 4.3 Jelly Bean should arrive on Sony Xperia ZL sometime in mid-December, though the release date has yet to be confirmed.