Amazon RDS for Oracle now supports the October 2019 Patch Set Updates (PSU) for Oracle Database 11.2 and 12.1, and October 2019 Release Update (RU) for Oracle Database 12.2 and 18c.

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/amazon-rds-oracle-supports-oracle-patch-set-updates-release-updates/