oo_ used but undefined in +occbin/kalman_update_algo_3.m

Line 259 of matlab/+occbin/kalman_update_algo_3.m reads:

                    [~, out, ss] = occbin.solver(M_,oo_,options_);

But oo_ is undefined in that file.

I encountered this error when running calib_smoother after occbin_setup.