Not all the music for all instruments changes every two years even for the classical syllabuses. The flute one I believe is staying the same, and the current and previous viola syllabuses are the same. I think instruments which have masses of music change more often, and the music comes around possibly less frequently (people seem to be learning for violin grades 4-5 music that I did when I did those exams

makes me feel old!) but having syllabuses that are more than 2 years old isn't that unusual I don't think.