Yesterday I upgraded from 15.0 to 15.1. Everything went flawlessly, except that now I can’t no more sudo. I checked with Yast, the rules are the same as for another computer running Tumbleweed. I even tried to replace the sudoers file generated by the installation program with the one saved during the upgrade (sudoers.Yast2.save), nothing works…
You mean you booted from it and then choose the Upgrade option from the menu?
Another option to upgrade using the DVD would be to install fresh from the DVD while keeping your data (/home, etc.).
Is that the the update applet that uses Packagekit?
Personaly I would prefer YaST > Online update, or zypper up.
What I mean is that I didn’t upgrade via an obscure recipe obtained from an old guru on a full moon night behind the cemetery during a voodoo ceremony that could have resulted in a broken system.