Heroku has migrated its multi-tenant PostgreSQL database fleet from a self-managed environment on Amazon EC2 to the Amazon Aurora PostgreSQL-Compatible Edition, improving operational efficiency and customer satisfaction without impacting customers. This transition involved moving over 200,000 databases, utilizing a dual control plane approach and specialized transfer systems for efficient data migration. The new architecture allows Heroku to leverage AWS Cloud services more effectively, alleviating the operational burdens on engineering teams and enabling a focus on customer value. The migration also positions Heroku to introduce advanced features such as AI-enabled database administration and enhanced security measures.