- Android 4.1.2 Jellybean
- Google Now™
- Expandable, actionable notifications
- Android Beam™ to send photos and more
- QuickTranslator application downloadable from the Application Manager
- Smoother user interface. Vsync timing across all drawing and animation done by the Android framework, including application rendering, touch events, screen composition and display refresh; and triple buffering in the graphics pipeline.
- User-installable keyboard maps
- Ability to turn off notifications on an app specific basis
- Shortcuts and widgets can automatically be re-arranged or re-sized to allow new items to fit on home screens
- Bluetooth data transfer for Android Beam
- Improved voice search
- Improved camera app
- Android mobile version of Google Chrome replaces stock Android browser
- Ability for other launchers to add widgets from the app drawer without requiring root access
Interestingly, this build is labeled as LS970ZVA, whereas the build that was rolling out to some users in February was LS970ZVB. We're guessing that other build was slightly newer, and that for some reason the ZVA build was chosen over ZVB for the wide rollout. Or Sprint made a typo over at the Sprint Community Forums. The latter sounds a little more plausible.
If you look at the changelog, there's actually a pretty big item hidden in some technical jargon about vsync timing and drawing by the Android framework - that's Project Butter. Project Butter does not just automatically work when a handset is upgraded to Jelly Bean. The OEM actually has to go into its own software overlay and rewrite portions of the code to take advantage of the Project Butter improvements, and this is by no means required. So, not every handset running Android 4.1 out there actually uses Project Butter (COUGH HTC ONE X+ COUGH), but LG apparently has chosen to do so on the Optimus G.
You should receive the update over the air in the next 10 days according to Sprint.