Use of Heroku AWS security group and account id is deprecated and will stop working
Change effective on 16 June 2021
Heroku previously published our AWS security group and AWS account ID for users to grant Heroku apps access to other services running on AWS. This information was removed and the approach deprecated 8 years ago. Heroku is changing the infrastructure that powers Common Runtime and the AWS account information that we removed 8 years ago will become invalid. See the original deprecation notice for alternative approaches to securing access to non-Heroku AWS resources.