However I was curious how can I perform and upgrade when a new version is out e.g. Firefox 7.0.1 to Firefox 8.0?
I decide to search around and came across this post in VMware Blog. It not only allow me to understand how to perform an upgrade over the old MSI, it also help explained the MSIProductCode, MSIUpgradeCode and the MSIProductVersion.
The upgrade code is very important especially in my example above. It will have different MSIProductCode due to the version change however, the MSIUpgradeCode has to be the same in order for View to detect this is an upgrade and to uninstall the previous away when you place a higher version of MSIProductVersion.
As the post in the blog mentioned, you can put MSIProductVersion from 1.0 to 2.0. You can also do incremental from 1.0 to 1.1 as well which is useful for build level upgrade rather than a version upgrade.