Patching and upgrading

One benefit of Amazon RDS for Oracle is the ease of maintenance. AWS does all the undifferentiated heavy lifting work behind the scenes so that your attention can be on applications and users. You can enable maintenance options during setup. Amazon RDS for Oracle will then automatically apply operating system (OS) patching, Oracle database patching, and minor database version upgrades in a predefined maintenance window.

With Amazon RDS Custom for Oracle, because you have database administrator privileges and operating system root access, you're responsible for patching and upgrade activities instead of AWS.

Responsibility	Amazon RDS for Oracle	Amazon RDS Custom for Oracle
Automatic OS patching	Yes	No
Automatic Oracle patching	Yes	No
Automatic minor Oracle version upgrades	Yes	No