System is running 1.9.0.0 and we inherited the theme from another company. If we apply SUPEE6788 everything appears fine, but if we go to Sales > Orders in the admin panel we get a 404 page not found error.
This tool will allow you to see what routes have changed in admin
https://github.com/brentwpeterson/magento-patches/tree/master/ParadoxLabs
There is a "Fix" function but I don't recommend running this is production.
