I have the next case:
I have as source code versions from 3.7 to 4.0.
Not so long time I've installed the site on production server by publishing from Visual Studio.
Now I want to Upgrade from 3.7 to 4.0.
I read that article http://docs.nopcommerce.com/display/en/Upgrading+nopCommerce
For me unclear is the first sentence of step 5 - "Remove all files from the previous version." There is mentioned exception for two files, but I suppose that:
1) most the plugins dont have version specific references so unless there are any breaking changes the files of the plugins don't have to be deleted.
2) Also my image files of products and categories are stored on the disk on the server so the directory Content/Images should also remain.
Am I right for 1 and 2?