My Understanding, is that until 1.0 the recommended way to upgarde is clean install only. Says that on their web site also.
Here is a quote from Moshe, one of the team emembers when I asked about upgrading…
1. leave your existing copy of files and database.-- Ny personal note-- save the entire installation elssewher if you can, as you will need certain folders that have images, your changes etc and wipe out the current htdocs, all of its contents, then upload new upgrade files, run install.php
2. Create a copy of your database
3. Create new Magento installation connected to the cloned database,
4. Copy your changes (which should be separate files smile ) to new copy
5. Resolve incompatibilities.
then my own notes. This all went well going from 0.7 to 0.8
images are in **htdocs/media/catalog
logo.jpg and gif jpg not used
**/htdocs/app/code/core/Mage/Page/etc/config.xml (Welcome to Epeicure Cookware etc)--delete /var/cache
yes left_callout is correct, though its on the right?? its the cust svc 24x7 pic
some ofo those notes apply to my specifics, but the general paths etc are correct. Hope that helps some.
I have yet to try same on this latest upgrade but suspect the same method will be fine. Fingers crossed.