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's latest iPhone 5S has an unexpected feature: the Blue Screen Of Death (BSOD). While it's typically an error found on older Windows PCs, a number of iPhone 5S users are reporting random reboots on their handsets following a BSOD.