This chapter provides an overview of the upgrade process and upgrade environments, and describes the utility used to perform the upgrade. Also review the topics that are relevant to the z/OS upgrade in the chapter of the Siebel Database Upgrade Guide that describes how the Siebel database upgrade works. This chapter includes the following topics:

• About Supported Upgrade Paths
• About Using Oracle's Application Expert Services
• About Unicode Support
• About Siebel Upgrade Environments
• About the z/OS Upgrade
• About the Staging Database
• About Siebel Additive Schema Upgrade Changes
• About the Siebel Database Upgrade Process
• About the Database Configuration Wizard
• About the Siebel Upgrade Wizard and Driver Files
• Job Flow of a Production Database Upgrade
• About the Override File
• About the Siebel Database Configuration Utilities