Finally, I did my update.
The problem was that I was running Debian Buster, so I first had to upgrade to Debian Bullseye so that the installer could install the new packages.
Then, I made a copy of the fogproject/ folder, deleted the folder to initiate a git clone
Next, I followed the tutorial and restarted the installer, which restored my old settings. The web interface is working, so I assume my clones will work as well.
Thank you.