Allegedly, the change to the computer system can take up to 24 hours, so in theory, we may have to manually do it for the first day. (after all, there are 24 time zones, and what is midnight in BOS is only 11PM in Chicago, 10 in DEN, 9 in LAX...)
Every CS agent I know has been briefed on the 1st 24 hours thing not going to go smoothly.
Most of our computers default time (from the programming side) is set to Zulu, which obviously passed prior to BOS time, so the anticipated lack of ability is as expected.