In this chapter, we talked about the three types of updates. Major upgrades are the easiest to do, but are the least efficient for small sets of changes. They perform a complete uninstall of any older versions of your software. Minor upgrades and small updates are typically delivered as patch files and are smaller in scope. They only replace some of the existing files and add new features, but don't take any away. These can be an ideal method for keeping customers up-to-date on bug fixes.
In the next chapter, we'll see how to add new functionality to WiX by building our own WiX extension. It will be of the same variety as WixUIExtension or WixUtilExtension. You'll see that once you've associated your custom WiX elements with custom actions, the sky is the limit.