Sun Java Enterprise System 5 Update 1 Upgrade Guide for Microsoft Windows

Upgrade Web Server Dependencies

It is generally recommended that all Java ES components on a computer system (and in a computing environment) be upgraded to Release 5U1. Release 5U1 Web Server has no hard upgrade dependencies, but upgrade is only certified when shared components have also been upgraded. The upgrade from Release 5 to Release 5U1 requires that Windows Installer patch (126910–02) is already applied.