  We classify the finite irreducible modules over the conformal superalgebra
$K'_{4}$ by their correspondence with finite conformal modules over the
associated annihilation superalgebra $\mathcal A(K'_{4})$. This is achieved by
a complete classification of singular vectors in generalized Verma modules for
$\mathcal A(K'_{4})$. We also show that morphisms between generalized Verma
modules can be arranged in infinitely many bilateral complexes.
