Given boost uses version numbers x.y.z such as 1.30.2 1.31.0 The build system generated libs and stuff with -1_31 appended. I have a few questions about this: How is this generated? We wish to build our own version of boost (based on one of the above releases, but with patches) so wanted to version it accordingly. The obvious way would be for us to version it 1.31.0.1 so it is differentiated from the official 1.31 release. Unfortunately, boost only appears to support the x.y.z format. So we could number it 1.31.1 and hope boost doesn't release a 1.31.1. But I've edited boost/version.hpp to be 103101 and 1_31_1 and also the jamrules file to be 1.31.1 but the build-generated libs are still only post-fixed with -1_31. Where does the bulid system pick up the version number so I can modify it for the build and would it be easy to modify it to support w.x.y.z format so we don't run a risk of coliding with boost versions? Thanks Russell