Relevant code changes:
- the Project Id attribute is auto-generated
- UpgradeCode attribute is set (and is constant between versions)
<Product Id="*"
...
UpgradeCode="B28B3FA8-9310-4AA7-B0CA-CBCCA5FD00B2"
...>- MajorUpgrade element is added
- by default, it forbids the installation of an older version
- the default value of the Schedule attribute is afterInstallValidate
- removes the installed product entirely before installing the upgraded product
- if the installation of the upgraded product fails, the machine will have neither version installed)
<MajorUpgrade DowngradeErrorMessage="A later version of [ProductName] is already installed. Setup will now exit." />- once installed, this installer is upgradable
- after installing version "1.0.0.0" of the installer, FileToInstall.txt is deployed to the installation folder and an entry is visible in Windows "Programs and Features"
- after modifying the version in the wxs file to e.g. "2.0.0.0" and modifying the content of FileToInstall.txt, a new installer can be built
- trying to install that installer will
- first, uninstall the old version and then install the new version (order defined by MajorUpgrade.Schedule)
- FileToInstall.txt in the installation folder will be updated with the new one
- a "2.0.0.0" version entry will replace the "1.0.0.0" one in Windows "Programs and Features"
- trying to install an older version than the one installed will result in the error message (the one specified in MajorUpgrade.DowngradeErrorMessage)