The VGM package sources are available from the vmc-project organization in GitHub.
Development version:
git clone http://github.com/vmc-project/vgm.git
Tested with Root 6.28/04, Geant4 11.1.p1 (with embedded CLHEP 2.4.6.2.)
The last tagged version (5.2):
cd vgm
git checkout v5-2
Tested with Root 6.28/04, Geant4 11.1.p1 (with embedded CLHEP 2.4.6.2.)
The list of new developments, bug fixes and the required versions of ROOT and Geant4 for each version can be found in the VGMhistory.txt file.