Google I/O is going to start in just few minutes and Android 4.3 Jelly Bean is leaked aka confirmed on Google Developer Page. It looks like, this Android Version is indeed going to be announced in this event. You can watch the LIVE Stream in this Post.
According to Rumors, Android 4.3 is expected to bring Support for Bluetooth Low-Energy and the OpenGL for Embedded Systems 3.0 Graphics Specification.