Android 4.3 is an incremental update in the "Jelly Bean" version series which debuted with the new Nexus 7 (2013). Please only use this tag if you feel your question is specific to Android 4.3.
Announced on July 24, 2013, Android 4.3 is an incremental update to Android 4.2 which maintains the "Jelly Bean" moniker. It was launched on the new (2013) Nexus 7 tablet, and introduced several notable new features, including:
- OpenGL ES 3.0 support
- Bluetooth Smart, aka Bluetooth Low Energy
- "Restricted profiles" for multi-user accounts
- hardware-based encryption for video
The full release notes can be found on the Android Developers site.