my device is 14w23 and i have the call quality problems ! as in the other party struggles to hear you , or they get feedback. and it makes no difference if that to a land line or another mobile. i have spoken to Sony UK, and they told me to do a "repair" doing PC companion, which i did and all credit to Sony, they rang me back a few hours later to see how the fix went. well it obviously didn't work as the lady i was speaking to was getting feedback, and since then the problems still exist. as i bought the phone from phones 4U and not Sony directly , my next thing is to return the phone to them and let them do a repair . but not knowing if this is hardware or software issue . im not holding out much hope that the problem will be fixed ? all i know as i use the phone for my business i cant keep on using a phone my clients struggle to hear me on