If you started any version of GarageSale 7 today, you probably saw the warning about your version of GarageSale being a pre-release version, which is going to be expire soon.
For now, please ignore this warning and click the OK button to use GarageSale. We will have new release out any moment, which will remove this panel.
This warning is a left-over from the development stage of GarageSale 7, which everybody at iwascoding forgot about.
My apologies for the caused confusion.