Please note that the link you provided does not contain a firmware for your device (AG2 is slightly different to C67ML). The correct one is here:
http://www.onyx-international.com/in...e-for-artatech . Please note also that this is not official ArtaTech firmware since they stopped the device support after breaking their relationship with Onyx.
The current firmware upgrade was pretty smooth process in my case. You can read on the firmware page about changes and features removed from original ArtaTech software. Besides of some GUI refresh I don't see major differences. Maybe battery life is a bit better.