I have had an iphone 5 for a year. No problems with it. I updated to IOS7 and after about a week I got a warning message that said 'no sim detected'. The phone signal disappeared at this point and 'no sim' appeared where it would normally have the dots and 'LTE'. Turned phone off and on and signal came back. I have had this happen 3 further times, twice yesterday. Each time it has corrected after a power cycle. Anyone else seeing this?