You'll have to review and accept the i Tunes Software License Agreement before the new version will launch.
When you have i Tunes open, connect your i Phone to your computer using its USB cable.
The combination will work, but it may be slower or more problematic than you'd like. In terms of modern consumer technology, that's ancient.This is the scenario facing owners of the i Phone 4. To help you make an informed decision, I've compiled the reasons in favor of and against upgrading an i Phone 4 to i OS 7 below.Whether you upgrade your i Phone 4 to i OS 7 is up to you, of course, but I'd be cautious.If you're willing to live with some bugs or slowness and just have to have the latest OS, go for it. New phones are much faster, have bigger screens, can store much more data, and have better cameras.Other than the cost, there's really no reason to continue to use an i Phone 4 at this point. That gives you the best of both worlds: you'll get a fresh, fast new phone with all the latest hardware features and the latest version of the i OS.