How to prevent downgrade a major upgrade
I am working on this product.
We have had a major upgrade recently (changed product code). But later we found out that users can install the previous version and the worst part is that they can install it successfully and they will end up having 2 versions of the product on that same machine.
1. How can I patch that up and Eliminate the problem
2. How to prevent this in later versions that will be built in the future?
Thanks for reading! Any answer is appreciated!
Under Upgrades > Upgrade Windows Installer Setup there should be an entry ISPreventDowngrade which InstallShield puts there by default to prevent this problem. Is this missing in your project? (Maybe your project was originally created in a much older version of InstallShield thata didn't have this entry). If the entry exists and never altered (you don't have to adjust anything there, it all happens automatically during build) then make sure that the UPGRADECODE has not changed between these versions and that the version number has been incremented in any of the first three fields (not just in the fourth.
InstallSite.org / InstallSite.de
If the ISPreventDowngrade item is missing from your project - we have instructions on how to manually add it back in here: