The Installable Unit build differs from the installed one

You cannot update a newer InstallableUnit with an old one.

Note: The InstallableUnit contains the feature, but adds several installation files to it. These extra installation files can also change. Therefore the IU also needs a build number.

To update an InstallableUnit, such as Web UI, that has a dependency, such as Tomcat, you may also have to update the dependency. If the dependency is not available, or does not have the right version and build, you cannot update the InstallableUnit.