The big one is, the two separate animated program categories (one for
shows less than one hour, and one for shows one hour or more) have
been combined into a single category. It is not clear if an hour-long
episode of a series is still allowed to be entered separately from a
regular-length episode. (The rule might be the same as the one for
live action shows - in which casem, it would have to be more than
twice as long as normal to be eligible as a separate show.)
The other one is, the "special class short format animation" (the "15
minutes or less") area has been changed to a "proper" category. This
means that if there are at least two nominations, like there were last
year, then there must be a winner - which there wasn't last year (and
the Academy didn't bother to tell anybody (presumably outside of the
nominees) in advance, or even say something during the Creative Arts
awards that there would be no winner in the category that year).
-- Don