RadSim v4.1 has been released. This has been updated to work with RTTOV v14.1. New features include: support for new RTTOV capabilities including MFASIS-NN aerosol simulations and new simulation options, option to specify a range of channels to simulate instead of an explicit channel list, and support for temporal interpolation between ECMWF GRIB fields at multiple analysis times (not only multiple forecast times). A full list of updates is here.