Under RDS AWS console you will see recommendations as mentioned below.
You have pending maintenance available on your DB instance. Updates to the operating system most often occur for security issues and should be done as soon as possible.
- Go to AWS console > RDS > Databases > Click on RDS cluster
- Click on Maintenance and Backups
- Under pending maintenance select the patch and click Apply now
4. Patch installation will complete with in 10 to 15min.