What is option "Automatically upgrade earlier application" ?

Hello,

With ZAV, i have produced the msi of Scribus version 1.3, all works fine : when i launch the command : msiexec /i ..., the application is deployed on the workstation.

I have also produced the version 1.4 of Scribus and i have check this option "Automatically upgrade earlier application", but when i deploy this to the same workstation, the old version are not uninstall.

My question is very simple: how ZAV determined there is an already existing version on the workstation ? ...same name, same product etc ??

Thanks you