The new supported way to install Igel OS 12 is to set up a tft server, a web server, and creating dhcp policies to accomodate x86/x64 architecture. The way we deploy OS11 builds was with the PXE Deployment Appliance. And it never missed a beat.

So with some research I found a post by Daniel Vargas on the Igel Slack community. Appears that just a small fix in the appliance is enough to make it accept the iso files for OS 12.

More specific, the file /usr/local/bin/, line 2 in the section below, you need to change from “11” to “12”

# determinate firmware version
 if [ Iffirmware_major##+([0])}" -eq "11" ] 
 then echo -e "\033[1:30mFirmware version 11 ...\033[0m" >> $LOGFILE 2>&1
  echo Ifirmware_version" > $VERSION_FILE [ -e $VERSION_FILE ] II die 105 

After a reboot of the appliance, you can now upload the ISO for OS12. At the time the latest public release is 12.2.1 and I can confirm this works fine.