Common Runtime infrastructure upgrade and required DNS changes

Change effective on 26 May 2021

The infrastructure powering Common Runtime apps is being upgraded. The upgrade process started in April ’21 and will continue over the next couple months. Apps running on the upgraded infrastructure will see improved dyno performance and improved regional reliability and uptime.

The upgrade process is designed to be seamless and to not require user involvement. Apps with unusual DNS configurations or with unusual clients accessing the app may see errors, however. It is important to verify your DNS set up is correct with the information below, by July 31, 2021, to ensure your app will still continue to be accessible post-migration.

When an app is migrated to the new infrastructure its default DNS records, and any custom domain records are modified to point to the IP addresses of the new routing infrastructure. For a period of 24-48 hours, the app is accessible via both the new and old routing infrastructure. When the migration completes, the app will no longer be accessible via the old routing infrastructure and all traffic must flow via the new infrastructure. Requests for an app sent to the old infrastructure will result in H31 Misdirected Request Errors.

If you encounter H31 Misdirected Request Errors, please reference this knowledge base article.

For more information and examples of incorrect setups that may work with previous-generation Common Runtime infrastructure but will break when an app is upgraded, please see this knowledge base article.