Panasonic GH4 firmware update
Seems there are many new functions like post focus (set the focus point after shooting and save as a separate photo), 4K photo mode, burst shooting with external flash (with Panasonic External Flash DMW-FL580L / DMW-FL360L ).
There are some performance improvements as well
-Red eye reduction in RAw files improved
-AF On function can be used during video recording
-The time lag of stop signal transmission through HDMI is adjusted to make the length of the recorded contents same either on the SD Memory Card or on the external recorder via HDMI.