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 reveals waterproof iPhone 7 with new camera ... and no headphone jack. Apple has unveiled the iPhone 7 and 7 Plus, its next generation smartphones, which have a similar aluminium look but now waterproof with new insides, new pressure-sensitive home button, new dual-camera features and no headphone socket.