Some major security Vulnerabilities that iOS 8.3 fixed are denial-of-service issues, a cross-site cookie issue, and a bug that could allow a website to install malware. The update also updates the certificate store.
The iPhone 4 users cannot enjoy the iOS 8.3 because the OS system supports iPhone 4s and upper versions. The company didn’t disclosed the all security vulnerabilities that they fixed in this update but we believe that the new update will make Apple users more secure than any other smartphone users.
iOS 8.3 also makes Apple Pay more secure.Recently companies like PayPal has raised questions about the security of Apple Pay. Update also fixes bugs in Safari browser, Face-time, iMessages and fixes the WiFi Problems which many users has reported previously. The update also enables the WiFi calling in the Sprint carrier which was a major issue for the Sprint users.