Immediately after installing IOS 7 (on about 9/19), I noticed that the lock-screen access to Music was not working. I could change the volume and timepoint of a song that was already playing, but the play/pause, forward and rewind buttons did not work. Some posters suggested that a restore would fix the problem, so I restored and am now at 7.0 (11A465). After the restore, the controls worked for a day or two, but stopped working again. And I've noticed that the same functions are not working with Bluetooth in my car.
BTW: the restore did not preserve the set of downloaded e-mail. Those messages are gone, so far as I can tell.
iPhone 4, iOS 7, Upgraded ~9/19, restored ~9/22