UpgradeCode and detecting related bundles

In this section we will find out how to detect and update older versions of your bundle.

Updating existing bundles

Each time that you compile your bootstrapper project in Visual Studio, it is assigned a new identity—a GUID called BundleId that you cannot change. In this respect, every bundle that you create is unique. The UpgradeCode attribute allows us to link two bootstrappers, making them related bundles. This relationship allows one bundle to detect and upgrade the installed packages of the other.

The UpgradeCode attribute is set on the Bundle element, as shown:

<Bundle Name="Awesome Software Bundle"
        Version="1.0.0.0" 
        Manufacturer="Awesome Company"
        Copyright="(c) All rights reserved."
        UpgradeCode="3601032C-A8C9-4323-88E0-1967A9C2145E">

Now, having two bundle executables with the same UpgradeCode attribute does not mean that one will automatically replace the other. Their versions have a big part to play. Two...