Retina upgrade. The newly released iPhone 4 further ups the gaming ante with its visual enhancements—specifically the 960-by-640-pixel Retina display at the heart of the phone’s new form factor.

Now, IOS 4 makes the iPhone capable of running multiple applications simultaneously. Folders: Users can now better organize their iPhone apps with home-screen folders to cut down on clutter.

The iPhone 4 no longer gets iOS updates. After almost a decade of support, Apple’s iPhone 4 has finally reached its end-of-life (from a software perspective). In fact, the iPhone 4’s last iOS update ...