  The coherent potential approximation has historically allowed the efficient
study of disorder effects over a variety of solid state systems. Its original
formulation is however limited to a single-site or uncorrelated model of local
substitutions. This neglects the effects of correlation and short range
ordering, often found in realistic materials. Recent theoretical work has shown
how to systematically address such shortcomings, for simple materials with only
one element per unit cell. We briefly review the basic ideas of these
developments within the framework of multiple scattering theory, and suggest
their generalization to materials with complex lattices and possibly different
types of disorder. We illustrate this extension with an example of local
environment effects in the exotic Hapkeite $Fe-Fe_{37.5%}Si_{62.5%}$ compound.
