I have just updated to Dazzling theme from 1.5.1 to 2.0, - I have noticed that all pages now have right sidebar as layout. when before the update I had full width set as default in my layout options. It took me a little while to work out. I had to navigate to Appearance > Customize > Dazzling Options > Layout Options and in Website Layout Options change it from Right Sidebar to Full Width again.
Does updating your themes not retain the previous user defined layouts and options?
I thought all settings would be migrated.