Geant4 offers a set of models to simulate hadronic showers in calorimeters. Recent improvements to several models relevant to the modelling of hadronic showers are discussed. These include improved cross sections, a revision of the FTF model, the addition of quasi-elastic scattering to the QGS model, and enhancements in the nuclear precompound and de-excitation models. The validation of physics models against thin target experiments has been extended especially in the energy region 10 GeV and below. Examples of new validation results are shown.