Hi
This upgrade is available now but be careful. I upgraded to 4.3 using Sony PC Companion. Although I followed the instructions exactly, following the upgrade, the phone was sluggish with many apps 'not responding'. This is well documented on the web for many users of Xperia SP. After getting fed up with this, I did a factory reset on the phone, ensuring I ticked the box to remove all my data from internal storage. Then I went back on PC Companion and used the 'repair' option. Phone now working perfectly. battery life is MUCH better. wifi signal is MUCH better. mobile signal is MUCH better. No sluggishness or apps not responding. The phone is working like it always should have done.
If you can be bothered, it is worth it, although there is a good change it will not work first time and I definately recommend a factory reset before you start
