  The Monte Carlo for lepton pair production andtau decays consist of KKMC for
lepton pair production, tauola for tau lepton decays and photos for radiative
corrections in decays.
  An effort for adaptation of the system for precision data being collected at
the Belle II experiment included simulation of additional light lepton pairs.
Extension to processes where lepton pair is produced through narrow resonances,
like dark photon or dark scalar phi resonances, was straight forward.
  Modified programs versions are available in stand-alone format from gitlab
repository or through the basf2 system of Belle II software. It was explained
recently during the International Workshop on Tau Lepton Physics September,
2021, Bloomington IN. Now we concentrate on simulations for phi resonance, a
hypothetical object which could be responsible for anomalous moment g-2 in
Z-\tau-\tau interactions through virtual contributions.
