So far we have only been migrating users to Movable Type Enterprise (MTE) 4.x upon request. Quite a few users still manage their blogs through our legacy installation at blogs.princeton.edu/mt.
The mixed environment of Princeton LDAP and non-LDAP users forced us to keep that version of Movable Type Enterprise at 1.0.3 (MTE 1.x is equivalent to MT 3.x). This was an undesirable security risk. The recent introduction of the Guest Account Provisioning (GAP) service allowed us to remove non-LDAP users from the system, freeing us to move to MTE 1.56.
Users should not have noticed any minor changes to the user interface; most of the visible changes in this version dealt with user management. Those with questions about the updated version, or those who would like to migrate their blog to MTE 4 should contact email@example.com.