I tried to follow the https://www.virtualmin.com/documentation/installation/uninstalling
However, I was not able to see any change from pro to GPL, I still have the pro feature.
In fact, here the steps I made so far.
# deb http://5574682:firstname.lastname@example.org/vm/6/apt virtualmin-bionic main
# deb http://5574682:email@example.com/vm/6/apt virtualmin-universal main
deb http://software.virtualmin.com/gpl/ubuntu/ virtualmin-precise main
deb http://software.virtualmin.com/gpl/ubuntu/ virtualmin-universal main
Then (I am confused with this section if I made the right changes) apt-get install webmin-virtual-server
[root@panel ~]# less /etc/virtualmin-license
However, I still have the Pro version. Could you shed some light?