DateTime::Duration now provides a compare() class method.
DateTime::Duration now overloads comparison to throw an exception, because comparison requires a base DateTime object. Note that previous versions of DateTime::Duration _did not_ overload comparison, so if you were comparing them, you were just comparing the value of the object references. Thanks to Rick Measham, Jon Swartz, and Max Maischein for contributing to the discussion on datetime@perl.org about how to implement this feature.
Added DateTime::Duration->multiply to complement multiplication overloading.
Added a leap_seconds method.
Added a section to the docs about floating datetimes.
DateTime::LeapSecond no longer contains code copied from DateTime.pm, instead it just uses DateTime.pm directly. Patch by Joshua Hoblitt.
BACKWARDS INCOMPATIBILITIES
DateTime::LeapSecond's leap_seconds() function now returns the number of leap seconds that have occurred, as opposed to the difference between TAI and UTC for a given Rata Die day, which is what it was returning previously. This means that the values it returns are 9 second less than the previous version. This does not affect DateTime.pm because it never looke at the actual value, just the difference between two leap second values, which remains the same.