In December, Penn's Kerberos authentication back-end will be upgraded to the latest version of MIT Kerberos in a series of three steps on December 4th, 6th, and 11th respectively, all at 8:00 AM. These upgrades will be applied to the three Key Distribution Center (kdc) servers, and will affect both the KDC and adminstration services, which manage Kerberos principal creation, modification, and password changes. The upgrades will be invisible to end-users and will not affect any existing or new Kerberos sessions.