Before you upgrade Oracle Restart, determine the best upgrade path, and run the procedures that are described here to prepare for the upgrade.

Oracle recommends that you test the upgrade process and prepare a backup strategy.

• Options and Restrictions for Oracle Restart Upgrades
  Review these upgrade options and restrictions when you upgrade to Oracle Grid Infrastructure for a standalone server (Oracle Restart) 19c.
• Checks to Complete Before Upgrading Oracle Restart
  Complete these preupgrade checks to avoid issues during the Oracle Restart upgrade process.
• Installing the Oracle Preinstallation RPM with ULN Support
  Use this procedure to subscribe to Unbreakable Linux Network (ULN) Oracle Linux channels for your Oracle software.
• Creating a Copy of the Preinstallation Configuration File for the grid User
  Create a copy of the preinstallation configuration file for the grid user to set hard and soft limits for the operating system parameters.
• Shutting Down the Database
  If your Oracle Database uses Oracle Automatic Storage Management (Oracle ASM) for storage, then shut down the database before upgrading Oracle Restart.