2GB is the size limit for the CAB files included in the MSI package. This is a windows limitation and not a limitation from Installshield.
The solution here is to build an uncompressed release as the cab files are no longer in the MSI file and therefore this limitation no longer applies.
It would be possible to create a compressed setup.exe, however there is also a Windows limitation of 4GB on a portable executable file.
Whilst you could apply different compression levels to reduce the overall size of the package, this will ultimatley impact the installation speed as the installer will then need to uncompress and write the files to a temporary location to install them. As the size increases, so will the compression - and so will the installation time.
Ultimately the ability to reduce the overall size of your application is at the development level of the software - and if this is not possible then an uncompressed release will be the best option.
InstallShield has comparable functionality. MSI-based projects (Basic MSI and InstallScript MSI) have an ISPreventDowngrade item by default that prevents the downgrade of a higher version to a lower version of a product.
Please give this a try. Does it work for you?
Please let us know if you have any questions or concerns. Thanks!
