  We present an update of the Mathematica package SARAH to calculate unitarity
constraints in BSM models. The new functions can perform an analytical and
numerical calculation of the two-particle scattering matrix of (uncoloured)
scalars. We do not make use of the simplifying assumption of a very large
scattering energy, but include all contributions which could become important
at small energies above the weak scale. This allows us to constrain trilinear
scalar couplings. However, it can also modify (weakening or strengthening) the
constraints on quartic couplings, which we show via the example of a singlet
extended Standard Model.
