I have had my iPhone 4s for a little over a year and a half. As of two days ago, the Verizon logo disappeared at the top of the screen. Overall service quality seems to be down as well. I have read similar threads on here regarding the same problem, however, most all point to an Alltel PRL number. All of these threads are one to two years old. The Alltel PRL theory makes sense, except in my case, where my phone has said "Verizon" for over 18 months now. My mother in law purchased a new 4s last week and I noticed hers didn't show the Verizon logo at the time. A few days later, my logo disappeared and so did the same on my wife's 4s. Is there anything new on this subject?