I need to upgrade from 2.3.7 to the current version. The instructions at http://doc.silverstripe.org/sapphire/en/installation/upgrading state replace system files but leave custom files. It mentions only a couple of each. Can someone tell me what files are to be replaced and what to leave? I would appreciate an answer for the novice. I inherited a silverstripe website and am having problems with the documentation as it seems to have been written to someone who fully understands the program and the programming of it. So please give some help to a novice.