According to the official Apple changelog, iOS 9.3.3 only contains minor bug fixes. It is likely the last version of iOS 9, since iOS 10 is less than three months away.
Below are the direct download links for iOS 9.3.3 IPSW files used to update and restore your device via iTunes. A full list of previous releases is available on our resource page.
Be sure to check out and bookmark our resource page which contains links to all iOS versions.
Jailbreakers please see this page to see if a jailbreak is available.