ATL09 pass-through data (cloud flag parameters) are now being written to ATL06 (gt[x]/land_ice_segments/geophysical/layer_flag). Note that if two flags intersect an ATL06 segment, the higher flag value is used. The layer_flag parameter is important for predicting forward scattering; The large DEMs previously used by ATL06 are no longer required inputs. If they are provided in the processing control file, the values are queried as in previous releases; if the DEMs are not provided in the control file, DEM values from ATL03 are used; Molecular transmission used to compute effective background is now being read from ATL09. Prior versions used a default value; Added radial orbit error as gt[x]/land_ice_segments/ground_track/sigma_geo_r (parameter sigma_h from ATL03); ATL03 data flagged with non-zero values in podppd_flag are no longer processed for ATL06; Changed the residual histograms to range from -50m to +50m with varying bin sizes; Corrected the long names for sigma_geo_at and sigma_geo_xt in the ATL06 file metadata; Residual histograms are centered on h_mean instead of h_li.