No calculations involve dates. In the Fortran code there is no Y2K issue.
All dates are text strings entered by the users, and no calculations involve any dates.
There is a Y2K bug in the interface, but it does not affect the run results. This is only a cosmetic bug and does not affect the results. This calculation does not affect the optimization results. If a run was started in 1999 and finished in 2000, it would give a negative elapsed time. Optimization results are NOT affected.