Suppose you shipped an app named "Hello", version "1.0", using VAInstall. You now want to ship a module or a plugin to this app "Hello" version "1.0". For example, you have a new DLL plugin ("new_plugin.dll") to add to the plugin/ dir of the "Hello" app. The process is similar to the upgrade.

You just have to build a package with VAInstall, containing the files necessary for the module or the plugin (only "new_plugin.dll" in our example), and with the same app-name "Hello" and the same version "1.0".

On the end-users machine, the installer will detect version "1.0" and force the installation in the correct base directory: "Hello"'s main directory.