Reply to Firmware v1.3 vs. v1.4 - How do I know which one I have?

How do I know if I have firmware version 1.3 or 1.4? I did the trick where you plug in the usb without loading the software, and click the button to the top right of the left trackwheel, and it does turn on and off while the one on the other side does not. Does this mean I have 1.3 only? Or is it possible I could have 1.4? Thanks