Samsung appears to be making good on its promise to port Galaxy S4 features to the Galaxy S III. A test Android 4.2.2 update, discovered by SamMobile, includes the lockscreen effects and widgets, enhanced screen modes, updated settings, and new S Voice control features found in Samsung's new flagship. Samsung previously said it would include updates that were "not dependent on hardware," ruling out gestures like Air View and the smart TV remote app.
The Android update is currently undergoing internal testing and is available as an unofficial pre-release ROM, suggesting that the company could add or remove features before an official rollout — which is reportedly slated for June. Given the unofficial nature of the ROM, we don't recommend that you install it at this time.