We are receiving a number of reports that the Android 4.2.2 Jelly Bean update is now available for the Xperia Z. Like with the Xperia ZL, the firmware build relates to version number 10.3.A.0.423.
We understand that the generic update is out in Spain and the Ukraine for the LTE model (C6603). Carrier customised versions are also out in Austria, Czech Republic and the Netherlands. A generic Taiwan update is also out for the HSPA+ version (C6602).
Thanks Allan and Colin!