@willian Upgrade will rewrite the DHCP config of your FOG server. So make a backup copy if you have modified it.
As well make sure you read und understand this before you upgrade: https://forums.fogproject.org/topic/13488/fog-1-5-7-officially-released
The other method is to use most of the stuff but for removing packages, source in the .fogsettings file before you remove the /opt/fog/ folder. Then you can use packagemanager-uninstallcmd $packages
Note this will simply remove the packages fog installs. All the other bits of service removal and what not should work as indicated.
I kind of side with @Sebastian-Roth however because removing all the installed packages can sometimes uninstall elements unexpectedly and out of “fogs” control. I’ve seen occasionally some like like installing python then uninstalling it breaking package manager tools like yum or apt
Technically you can probably capture and deploy it in a non-resizable fashion (it will be slow since it will do a RAW capture), though I’m not sure if this will work reliably with such a filesystem.
It’s closed source and only available on enterprise, so I don’t expect any open source solutions to arrive any time soon.