What controller do you have ?
I think the ONLY compatible controller for the Mini 2 is the DJI RC-232, you might know it as the DJI RC-N1.
If correct then there are no "upgrades".
Whoops my mistake, see the next post. Sorry about that.
By any chance do you mean you need to
update the firmware on your controller ?
If so download and instal the
DJI Assistant 2 (Consumer Drones Series)
At the DJI Download Center, learn and download DJI Assistant 2 (Consumer Drones Series)
www.dji.com
to your computer.
Boot the program, switch the controller on and connect it to the computerr via USB.
Ensure that you comply with any time scales but that might ONLY apply to the drone.
Once the program sees the controller I think you will see an firmware option/menu.
If so open that option and, at a guess, select the new firmware and install it. It may take a while so ensure the controller's battery is fairly well charged and keep an eye on the program. I haven't updated a
mini 2 controller but it is possible it might switch off and on several times during the update process, if so I magine the program will tell you that the controller is going to switch off.
When the process has completed I would suggest you reboot the controller after disconnecting the USB cable, just be sure that you yourself DO NOT switch the controller off whilst the update process is running.