Carry out these tasks to prepare your upgrade.

Before you upgrade your database, Oracle recommends that you review the new features and determine the best upgrade path and method to use, and carry out procedures to prepare your database for upgrade. Oracle strongly recommends that you test the upgrade process and prepare a backup strategy.

• Become Familiar with New Oracle Database Features
  Before you plan the upgrade process, become familiar with the features of the new Oracle Database release.
• Choose an Upgrade Method for Oracle Database
  Oracle offers several methods to upgrade your database, which support the complexities of your enterprise.
• Choose a New Location for Oracle Home when Upgrading
  You must choose a location for Oracle home for the new release of Oracle Database that is separate from the Oracle home of your current release.
• Develop a Test Plan for Upgrading Oracle Database
  Review these topics to understand how to create a series of carefully designed tests to validate all stages of the upgrade process.
• Schema-Only Accounts and Upgrading EXPIRED Password Accounts
  Before starting your upgrade, determine if you want to use password authenticate to default Oracle Database accounts where their passwords are in EXPIRED status, and their account is in LOCKED status
• Back Up Files to Preserve Downgrade and Recovery Options
  To ensure that you can recover from upgrade issues, and downgrade to an earlier release if necessary, Oracle recommends that you implement a backup strategy for your database, and for some specific files.