When building with a customized template in Repackager you may receive the following error: Error: Unable to upgrade the template file.
Workaround
Either use an InstallShield template from version 2021 or modify the schema of the template.
To change the schema:
- Open the template in Installshield.
- Via the Direct Editor, change the InstallShield Table by setting the Schema Version to 785. This is the schema version for IS2021.