iPhone slow? Why your new iOS 10-powered phone might feel slow after you upgrade

Two things happen like clockwork every September: Apple releases a new operating system to go on its new phones. And then everyone complaints that their old phones feel slow. The phenomenon – which can be seen in the huge surge in people searching for "iPhone slow" every year – is the result of a combination of factors. New software, the advertising of much faster new phones and heightened expectations that aren't always met combine to make the slab of glass and metal sitting on your phone feel like it's slowed down. But this year that seems to be even worse. And there seems to be something in it, after a huge number of complaints that iOS 10 slows down people's phones.