RDS Maintenance (2019-07)

We got email notification from AWS :

We are contacting you to inform you that one or more of your Amazon RDS DB instances are scheduled to receive maintenance on the underlying hardware between 2019-07-11 05:00 UTC (Thursday) and 2019-07-18 04:59 UTC (Thursday). You can view the scheduled maintenance time and perform opt-in actions on the RDS Console, using the AWS CLI or the AWS RDS API [1].

Region DB Instance Identifier Affected Availability Zone(s)
======================================================================
ap-southeast-1 busdata-postgres-01 ap-southeast-1b
ap-southeast-1 bxtbook-postgres-01 ap-southeast-1a
ap-southeast-1 entpsac-postgres-01 ap-southeast-1b

During the maintenance, single-AZ deployments will be unavailable for a few minutes.
For multiple-AZ deployment:

If the DB instance's 'Availability zone' is affected, a failover will occur. The instance will be unavailable for the time it takes the failover to complete, usually about 60 seconds.
If only the DB instance's 'Secondary zone' is affected, there will be no failover and no impact to availability is expected.

You can find an DB instance's current 'Availability zone' and 'Secondary zone' on the RDS Console. You can also obtain this information using the AWS CLI [2] or the AWS RDS API [3].

Please review the maintenance window or take appropriate opt-in action for each affected DB instance to minimize the impact of this maintenance on your application.

If you have any questions or concerns, contact AWS Premium Support [4].

Regards,
Amazon Web Services

[1] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_UpgradeDBInstance.Maintenance.html
[2] https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-instances.html
[3] https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBInstances.html
[4] https://aws.amazon.com/support