After I copied all the upgrade files, I got this: There are at least 4 file(s) that do not appear to have the expected contents. Reupload the XenForo files and refresh this page. Only continue if you are sure all files have been uploaded properly. I've reuploaded the data dir from install, same warning. I don't remember customizing anything else besides my custom theme. Is there a way to see which files are incorrect?