Upgrading the application:
It is often required that installed applications should be upgraded for the latest versions. Manually uninstalling the older version and installing the newer version application is a cumbersome job.
Once Again the responsibility is handed over to the operating system. Here, when an attempt is made to install the newer version of an application. The Operating System Service first uninstalls the older version of an application and installs the newer version.
Application Advertisement – (On-Demand Installation): For Product popularity an Effective Advertisement Strategy should be applied. That is, when the Main product or application is given to a customer the advertisement about the Sub-Products can be given. So that the customer get to know about the sub-products.
If the customer is interested in those sub-products he can request for those products. This feature is also called as “Advertisement Installation or On-Demand Installation”.
Application Patch: Sometimes it is required that some additional files, registry entries, or configuration files to should be set to the existing installed application (Patching up the application with the required data Instead of creating the newer version of installation package)
Note: Patches can be interpreted as Operating System Service Packs.
Central Point of Reference: It is required that a central point of reference for application installation be set. This is because whenever an application, which has been installed gets corrupted and needs to be repaired, from the same location from where it has been installed.
File Versioning Maintenance: Earlier, there was a drawback in setup installers. Say, there is a DLL of latest version and setup installer contains the same DLL of older version. When the setup is installed it will overwrite the DLL of latest version with the DLL of older version without performing any type of pre-check of versions.
This drawback can be overcome in MSI Installers. Where the file versions are maintained. That is, if there is already a file of latest version, it will be preserved during MSI installation.