Tarma Installer can detect the presence of a previous version of your product and uninstall it before installing the new version. This feature works regardless of the make and type of installer that was used to install the previous version and can be used during product upgrades.
If it finds a previous version of your application during the installation process, Setup offers to uninstall it before continuing. The check and the uninstallation are performed as custom Uninstall Product actions. By default, these are placed early in the MainInstall action sequence on the Action Sequences project page, but you can put them anywhere you like.
Note - Tarma Installer does not compare the previous and new versions of your application before uninstalling. Instead, it displays the uninstall title of the previous version and leaves it up to the customer to decide whether or not the replace the previous version. This allows both upgrades and downgrades.
Uninstallation of a previous application version is also supported during silent (unattended) installs.
To uninstall a previous product version, if present on the customer's computer, act as follows.
You can add further Uninstall Product actions for additional products, for example if your new product replaces several earlier ones.