Well I don't know then, it worked for me and the bugs seem to have resolved. It's worth a try again than rather waiting for Sony to release a new update. The latest firmware released uptill date is 15.3.A.1.17 in some countries and users are still complaining about the bugs, so you don't know when a reliable update might be launched!!!!!!
Some people are also suggesting to flash your device to a older version of jellybean, I have not tried that and not sure of the consequences. But as far as I know, older versions have more bugs than newer ones.