  We give here the final results about the validity of Jackson-type estimates
in comonotone approximation of $2\pi$-periodic functions by trigonometric
polynomials. For coconvex and the so called co-$q$-monotone, $q>2$,
approximations, everything is known by now. Thus, this paper concludes the
research on Jackson type estimates of Shape Preserving Approximation of
periodic functions by trigonometric polynomials. It is interesting to point out
that the results for comonotone approximation of a periodic function are
substantially different than the analogous results for comonotone
approximation, by algebraic polynomials, of a continuous function on a finite
interval.
