PHP4 (the current default) is being phased out on the server cluster, so we need to test all sites that use PHP to make sure they are using, or can use, PHP5. Stew and I started testing, and switching over all sites that were trivial and verified as working with PHP5. The only problem site we've found so far is Philosophy, which has some complicated code retrieving course listings from the calendar site; this appears to fail with PHP5, so we've switched it back to PHP4, and Stew will work on migrating it.