Since upgrading to IOS 7, the proximity sensor seems to be less responsive. For example, when answering a call and raising the phone to my ear, the phone alternates a couple of times between earpiece and speaker phone before settling on the earpiece. Also, when using Seri with the "Raise to Speak" feature, it never works. It cuts out in the middle of the command. However, Seri works fine when accessing it through holding the Home button. I believe this may also be as a result of problems with the proximity sensor. I am using IOS 7 with an iPhone 4S. Is anyone experiencing similar problems?