When will iphone 5 not be updated anymore?

After so many new phones come out through apple, they stop updating your phone once they don't sell it anymore and they give you one final update which will slow it down and force you to buy a better one. So i'm wondering when will the last update be released for the iphone 5?

IOS 8 is more than likely the last version of iOS the iPhone 5 and 5C will receive.