A small update makes changes to one or more application files that are too minor to warrant changing the product code. A small update is also commonly referred to as a quick fix engineering (QFE) update. A small update does not permit reorganization of the feature-component tree.
A typical small update changes only one or two files or a registry key. Because a small update changes the information in the .msi file, the installation package code must be changed. The package code is stored in the Revision Number Summary property of the Summary Information Stream.
The product code is never changed with a small update, so all of the changes introduced by a small update have to be consistent with the guidelines described in Changing the Product Code. An update requires a major upgrade to change the ProductCode. If it is necessary to differentiate between products without changing the product code, use a minor upgrade.
For information on how to apply a small update patch package to a Windows Installer package, see Creating a Small Update Patch, Applying Small Updates by Patching the Local Installation of the Product, Applying Small Updates by Reinstalling the Product, and Applying Small Updates by Patching an Administrative Image.