What does air updates mean for iphone?

If you live in virginia beach virginia and heard of the phone guys at ntelos in college park please respond. I bought a used iphone 4 and I want to update it but they said not to update air updates because it will just give you a better music app or something. I don't know if its ok too update the phone to iOS 7 if you have a used iphone.

Over the air update means to update via Wi-Fi by going to Settings>general>Software Update…

Hope you understand and helped you…