When I did an upgrade install of 5.6b3 over 5.5 I got a prompt asking me if I wanted to save my city to which I replied Yes. However, WW would not update the forecast due to an invalid city error. I had to reselect my city and Add it to the list. The difference between the two entries is one was just my city and state the other was those plus a code.
Even with all the things off that are mentioned in a previous posting about the weather wallpaper, I now have weather map wallpaper after the upgrade. Apparently Wallpaper Auto Update defaults to Every Minute.
I think on upgrades if the existing city doesn’t have the required weather code asking the user to keep it should be an option. And the default for an upgrade should be Never Auto Update for the Wallpaper.
PS Win XP Home SP2 system