I have an iPhone5 on IOS 7.0.6, and recently bought the Voyager Legend headset. It pairs easily, has great features, and audio quality on my end is excellent, however the qualify on the OTHER end makes it unusable most of the time. People I call complain of all kinds of electronic/robotic distortion. I upgraded the headset to the latest V99 firmware before pairing it for the first time, and have since reset the iPhone's network settings and re-paired, ...all to no avail. I'm in the process of exchanging the Legend and keeping my fingers crossed that the replacement will work. After reading posts of problems like yours and other iPhone users, coupled with this headset's rave reviews, I'm convinced the problem is with Apple software. Hopefully this will be addressed soon.