I had Ubuntu 8.10 and Deluge 1.1.5 (or earlier). I've upgraded my system to 9.04 and Deluge to 1.1.6. After that I cannot modify any settings in "Preferences" dialog, except notification and plugins. But I've noticed that I still have core.conf in ~/.config/deluge directory.
I can't download and seed now, please, help ;(
Cannot modify any settings after upgrade
Re: Cannot modify any settings after upgrade
Sorry, I resolved the problem. I had to start a daemon 
