The equals sign means is equal to. It is telling us that one thing equates to another; that they are the same.
The iPhone 4 is the most recent iPhone to be discontinued from the iOS Update cycle. It did not receive the iOS 8 update, so it's final software version is iOS 7.1.2. You can update to this version through iTunes, or download it from an IPSW repository like this website: https://ipsw.me/.
Apple released two new smartphone models, the iPhone 5C and 5S, and iOS 7, a new operating system, at the Apple campus on Tuesday, Sept. 10, 2013, in Cupertino, Calif. The term iPhone 5 was the third most searched term on Google this year and also appeared in Yahoo's top 10 search terms.