Apple replaced my 7+ out of warranty due to the 11.3 issue; mine acted like the headphones were plugged in, even when they weren't. It's an issue affecting early build 7 and 7+es. If you go in they will run a diagnostic and it will fail the audio part of it. Bear in mind this issue has only just been recognized by Apple. I didn't even push them to get a replacement since I bought it used and figured I got a bum phone.