Why didn't my RDS for SQL Server instance upgrade even though I have automatic upgrade turned on?

Resolution

Amazon RDS automatically upgrades the minor version of the instance in the maintenance window. This occurs if the newer minor version is set as the preferred minor version. However, if the newer released version isn't set as the preferred version, then Amazon RDS for SQL Server isn't upgraded.

Amazon RDS doesn't automatically set every newly released minor engine version as the preferred version. Before Amazon RDS designates the new minor version as the preferred minor version, the following criteria are considered:

• Any known security issues.
• Bugs in the newer Amazon RDS version.
• Overall fleet stability since the minor version was released.

If the new minor version contains significant bug fixes, then Amazon RDS schedules the upgrade for DB instances with the Auto Minor Version Upgrade option turned on. The upgrade occurs during the maintenance window configured for the DB instance.

Run the following AWS Command Line Interface (AWS CLI) command to verify that the newly released version is set as the preferred minor version. In the following command example, change engine, engine-version, and region to match your RDS for SQL Server instance configuration.

aws rds describe-db-engine-versions --engine sqlserver-se --engine-version 15.00.4073.23.v1 --region ap-southeast-2 --query "DBEngineVersions[*].ValidUpgradeTarget[*].{AutoUpgrade:AutoUpgrade,EngineVersion:EngineVersion}" --output table --color off

Note: If you receive errors when running AWS CLI commands, make sure that you're using the most recent version of the AWS CLI.

The following is example output for the command. This output indicates that the AutoUpgrade column is set to False. This means that the instance with version 15.00.4073.23.v1 isn't eligible for automatic upgrade to versions 15.00.4153.1.v1 or 15.00.4198.2.v1. This is because none of the newer released versions are set as the preferred version. The RDS for SQL Server instance won't upgrade to any newer minor version automatically.

-------------------------------------
|     DescribeDBEngineVersions      |
+--------------+--------------------+
|  AutoUpgrade |   EngineVersion    |
+--------------+--------------------+
|  False       |  15.00.4153.1.v1   |
|  False       |  15.00.4198.2.v1   |
+--------------+--------------------+