Validating Geant4 versions 7.1 and 8.3 against 6.1 for BaBar

Since 2005 and 2006, respectively, Geant4 versions 7.1 and 8.3 have been available, providing: improvements in modeling of multiple scattering, corrections to muon ionization and improved MIP signature, widening of the core of electromagnetic show er shape profiles, newer implementation of elastic scattering for hadronic processes, detailed implementation of Bertini cascade model for kaons and lambdas, and updated hadronic cross-sections from calorimeter beam tests. The effects of these changes in simulation are studied in terms of closer agreement of simulation using Geant4 versions 7.1 and 8.3 as compared to Geant4 version 6.1 with respect to data distributions of: the hit residuals of tracks in BABAR silicon vertex tracker, the photon and K(O)(L ) shower shapes in the electromagnetic calorimeter, the ratio of energy deposited in the electromagnetic calorimeter and the flux return of the magnet instrumented with a muon detection system composed of resistive plate chambers and limited-streamer tube s, and the muon identification efficiency in the muon detector system of the BaBar detector.