  We study the restricted Verma modules of an affine Kac-Moody algebra at the
critical level with special emphasis on their Jordan-H"older multiplicities.
The Feigin-Frenkel conjecture gives a formula for these multiplicities that
involves the periodic Kazhdan-Lusztig polynomials. We prove this conjecture for
all subgeneric blocks and for the case of anti-dominant simple subquotients.
