Downloading Release Update Patches
Download and install Release Updates (RU) and Release Update Revisions (RUR) patches for your Oracle software after you complete installation.
Starting with Oracle Database 18c, Oracle provides quarterly updates in the form of Release Updates (RU) and Release Update Revisions (RUR). Oracle no longer releases patch sets. For more information, see My Oracle Support Note 2285040.1.
Check the My Oracle Support website for required updates for your installation.
Parent topic: Required Postinstallation Tasks