This variable contains the Windows Installer version number from the target system as major.minor.build.revision. The installer sets this variable to the version of Windows Installer that is installed on the target system, if any. Note that this is independent from InstallMate's own version number VersionTin. If Windows Installer is not present on the target system, this variable is set to 0.0.0.0.
You can refer to this variable as <VersionMsi>. You can use the $vercmp function to compare the MSI version to something else, for example <$vercmp(<VersionMsi>, 3.0>. The variable is set automatically by the installer.
You can compare version numbers directly using the standard relational operators < <= > >= = and <>, so a conditional expression like VersionMsi < 3.0 will do a proper version comparison, obviating the need for the $vercmp function.