AWS Config now supports tracking changes to AWS CloudFormation stacks. A CloudFormation stack is a collection of AWS resources that you can manage as a single unit. With this release, you can now deep dive into the historical configuration of your CloudFormation stacks and review all changes that occurred to them. For example, you can now determine how your stack policies were changed or what updates were made to the resources within the stack. You can also receive Amazon Simple Notification Service (Amazon SNS) notifications when those changes occur. In addition, you can run a new managed Config rule to check whether your CloudFormation stacks are sending event notifications to an Amazon SNS topic.