With the Raspberry Pi connected to the Duet 2 WiFi via USB, power on the RPI and SSH into the Pi.

You can find the IP address of the Pi by looking at the connected client list in your router or by opening cmd.exe on your PC and running

ping mainsailos.local -4

In a webpage enter http://mainsailos.local or your printers IP address

Navigate to the Machine tab on the left.

Select Upgrade to update the RPI image and Update to install updates for Klipper, Mainsail and Moonraker. Once the updates are complete reboot the RPI