Hi Everyone, The newest release of FEFF8 is version 8.20 (according to the FEFF web site http://leonardo.phys.washington.edu/feff ). This version is also the most stable and fixes bugs in previous releases (8.10 , 8.00 and all experimental versions, which are designated with an x e.g., 8x39). In my view all earlier versions than 8.20 should be trashed. Matt is right that we haven't been consistent with version nomenclature, since 8.20 or 8.2 are often used interchangeably. Matt summarized well the differences between FEFF6 and FEFF8 in a previous message to this list. In my view, the key difference in FEFF8 for EXAFS is the availability of self-consistent scattering potentials and hence a better approximation of E0. In my opinion reducing the uncertainty in E0 should improve EXAFS analysis since this should also reduce uncertainties in distance determinations. However, the differences may not be that significant. Thus for EXAFS FEFF6 is often just as good. On the other hand, FEFF8 also yields electronic structure, e.g., charge counts, charge transfer, and densities of states, information which complements the structural information from EXAFS alone. A drawback in using FEFF8 is that getting the SCF loop to converge for complex materials can be tricky, and one of our challenges has been to develop a more automated procedure. Until that is available, we recommend always using the recommended defaults in FEFF8.2 in the SCF potential construction, unless one has good reasons for doing otherwise. We would be very interested to learn of cases where FEFF8.2 yields results which are inferior to those from FEFF6. J. Rehr