Good but I have no issue with the previous firmware also. What telco is yours and probably the issue lies on the settings for the Network.
My service plan (3G, no LTE yet) is from M1 and i have purchased Xperia Z from M1shop. The APNs should be predefined.
I am sure it has got to do with the phone firmware. Strangely, i don't see much issue when i roam but faced great difficulties when i am back home ground



