Moving towards the upcoming release of brand-new iOS 10, Apple has released the final version of iOS 9. Just so you know, iOS 9.3.3 does not bring any new feature. iOS 10, the next major version of iOS is being geared up for bringing exciting new features.
Instead, iOS 9.3.3 aims towards fixing bugs and improving security before the first version of shiny-new iOS 10 comes out this fall. The official iOS 9.3.3 changelog goes as following.
iOS 9.3.3 includes bug fixes and improves the security of your iPhone or iPad.
As usual, your compatible iPhone, iPad or iPod touch can be upgraded to iOS 9.3.3 via OTA (Over the Air) update or by using an IPSW file for a complete restore.
For hassle-free update, consider using OTA update. Go to Settings > General > Software Update and choose Download and Install. That’s it. Your device will be updated to iOS 9.3.3.
If you want to completely restore your iOS device using IPSW file, then download iOS 9.3.3 IPSW for your device using the links given below.
Note: If your device is jailbroken, it is advised NOT to upgrade to iOS 9.3.3 unless you want to lose the jailbreak. If your device is performing slow and you really wish to restore it, consider using Semi-Restore method. Learn How to Semi-Restore iPhone Without Losing Jailbreak.