This is the top-level container element for every wxs file. Among the possible children, the Bundle, Package, Module, Patch, and PatchCreation elements are analogous to the main function in a C program. There can only be one of these present when linking occurs. Package compiles into an msi file, Module compiles into an msm file, PatchCreation compiles into a pcp file. The Fragment element is an atomic unit which ultimately links into either a Package, Module, or PatchCreation. The Fragment can either be completely included or excluded during linking.
RequiredVersion (WixVersionType) : Required version of the WiX toolset to compile this input file.