[Setup]: AppVersion
Description:
This directive specifies the version number of the application being installed. The value of this directive, which may include constants, is used in the default value for the AppVerName directive, and is displayed in the Version field of the application's Add/Remove Programs entry. It is also used to set the MajorVersion and MinorVersion values in the Uninstall registry key when possible.
This directive is required and cannot be empty if the AppVerName directive is not set.
Example:
AppVersion=1.5