Update Firmware for Carplay
 

Hi
We have a 2014 Mazda 3 (Australia).
We want to install a USB retro kit so that our android phone can integrate with the Infotainment unit.
However, before we can do that, the firmware needs to be updated to at least v70.

So what I need is where to download the firmware.
There are plenty of you tube videos showing how to install the firmware and the retro kit, but none that I've found mention where to download the firmware.
Can anyone help?