Editing Windows Installer (section)

===Products===
A single, installed, working program (or set of programs) is a ''product''. A product is identified by a unique GUID (the ProductCode property) providing an authoritative identity throughout the world. The GUID, in combination with the version number (ProductVersion property), allows for release management of the product's files and registry keys.

A ''package'' includes the package logic and other [[metadata]] that relates to how the package executes when running. For example, changing an [[EXE file]] in the product may require the ProductCode or ProductVersion to be changed for the release management. However, merely changing or adding a launch condition (with the product remaining exactly the same as the previous version) would still require the PackageCode to change for release management of the MSI file itself.