I have a few projects where you can Install a new version then go back to a previous release and attempt to "upgrade" down to the older version. It should spit out a message saying a newer version is already installed. But it doesn't. It just closes the installer without a word. Anyone know how to configure the desired behavior here?
So normally installshield is supposed to handle this automatically with a custom action called "ISPREVENTDOWNGRADES" which is in the ui sequence right after findrelatedproducts (i believe).
For some reason this does not always work. I think something we do in several of our projects must break this. If you create a custom error and insert it into the action sequence before the default one then rebuild your solution it should work. I tested this by manually incrementing the version after a build and installing the one with the higher build number before attempting to install the older one. the error dialog then popped up.
Tried this same trick with another installer and it didnt do anything differently. Not sure what the deal is but this should at least work for some cases.
which had this important tidbit "It depends on whether you are changing the ProductCode (Major or Minor Upgrade) "
I immediately changed the productCode and tried a prevent downgrade. The dialog showed up as expected. So the difference is whether or not your action matches the type of downgrade it is preventing. In this case I think the installed version must be a valid major upgrade from the product you are trying to downgrade to in order to see the dialog.
Does anyone know how to do this with a minor downgrade?
