Elastic CI Stack for AWS v4.5.0 has been released 
Changed
- Added ImageIdParameter CloudFormation parameter, for SSM Parameter Store image lookup
Upgrading
Perform a CloudFormation stack update with the following URL:
https://s3.amazonaws.com/buildkite-aws-stack/v4.5.0/aws-stack.yml
If you want to launch a new stack, you can use this link (make sure not to use your production AWS account, create a new one for CI):