  A new implementation of estimating the two-to-two $K$-matrix from
finite-volume energies based on the Luescher formalism is described. The method
includes higher partial waves and multiple decay channels, and the fitting
procedure properly includes all covariances and statistical uncertainties. The
method is also simpler than previously used procedures. Formulas and software
for handling total spins up to $S=2$ and orbital angular momenta up to $L=6$
are presented.
