They changed all the numbers and consolidated them yet again.
I am not sure how the officer ones are done now (not that that applied to me).
I know they've done reorganization of the enlisted MOS system since I resigned my commission. Technically speaking, (commissioned) officers have Areas of Concentration or AOCs (and possibly later in their career a Functional Area) and warrant officers have warrant officer MOSs. Some of the recent changes have actually brought at least some of the branch codes into common. For example, when I was an MP officer, I was a 31A. The old MP enlisted MOSs were all 95 series, but they now also fall into 31 series, which used to belong to the Signal Corps.