Can i change my contract through the middle?

Ok so i have a iphone 5 and my contract is still on i pay 41 pounds a month and payed 100 pounds for the phone the insurance gave me a new one due to a cracked screen the one they gave me is faulty. So the new iphone 5s is coming out and i was wondering if i could keep the same contract but change the phone? If not is their anyway and if i need to pay how much? Please detailed answer 30 points for the best answer

You have to check with your provider, most will let you upgrade a few months early. You have to ask them.

btw - you can't give anyone 30 points.