The Revision Number summary information property contains the package code for the installer package. The package code is a unique identifier of the installer package.
The Revision Number summary information property of a patch package specifies the GUID patch code for the patch. This is followed by a list of patch code GUIDs for obsolete patches that are removed when this patch is applied. The patch codes are concatenated with no delimiters separating GUIDs in the list.
The Revision Number summary information property of a transform package lists the product code GUIDs and version of the new and original products and the upgrade code GUID. The list is separated with semicolons as follows.
Original-Product-Code Original-Product-Version ; New-Product Code New-Product-Version; Upgrade-Code
This summary property is REQUIRED.
Win32 MSI APIs: MsiSummaryInfoGetProperty, MsiSummaryInfoSetProperty