Upgraded to 2.64 by moving appropriate folders/files into MT or MT-STATIC. The instructions say to FTP up to your web server, but since I’m sitting here on the web server, I just dragged the files/folders in the right places, taking extra care to individually copy extlib folders in, since the upgrade contents of extlib are a subset and not replace.

Made exports of all blogs prior to upgrade, just in case.

I wondered if permissions would have to be set on new directories, but apparently not. Perhaps they inherit the parent folder’s permissions.