During the "life-time" of a certain engine it is updated from time to time and thus exists in different versions.
Latest for A6 is A6.60 afaik.
With these updates there sometimes are language changes, like adding specific commands or changing the syntax.
Thus I cannot tell you if c_rotate works with every freaking A6 version but it definatly does with the latest and I'm almost a 100 percent sure that it works at least since A6.31