It is not possible on the Windows platform to upgrade directly to Message Queue 4.2 from an earlier Message Queue version, but you can either uninstall the earlier version or install Message Queue 4.2 side by side with it at a different location in your file system. See Migration Issues for details on how to preserve data from such a previous installation.
The Message Queue 4.2 Installer does not share the same product registry with other installers, such as those of the Sun JavaTM Enterprise System (JES) and Sun Java System Application Server, which include Message Queue as a component. The Message Queue Installer also installs or upgrades shared software components that Message Queue depends on, such as the Java Software Development Kit (SDK), Netscape Portable Runtime (NSPR), Network Security Services (NSS), and JavaHelp. Using this Installer to upgrade an earlier version of Message Queue that was installed with another installer may upgrade such shared components without correctly updating their version numbers in the other installer’s product registry, leaving that registry in an inconsistent state.
If you later run the other installer, the inconsistent registry entries may in turn cause that installer to inadvertently remove Message Queue 4.2. The safest and cleanest way to upgrade an earlier version of Message Queue that was installed with a different installer is as follows:
Use the other installer’s uninstaller to remove Message Queue.
Use the Message Queue 4.2 Installer to install Message Queue 4.2.