I've followed the instructions for upgrading and cannot get past the admin authentication screen in upgrade.php. It roundtrips and comes back to the same screen with the fields empty and no error messages or anything.
The admin username and password are correct and I've tried it a few times. Now that main.inc.php and config.inc.php have been moved to includes, does the $configdir variable in main.inc.php need to be adjusted since it is no longer the same as $thispath? (which still points to the main install path, doesn't it?)
FYI, the problem was that his board was still using the old crypt style for the password, and it wasn't being recognized. The password was reset to an MD5 password in the database, and he was able to proceed.