You want to enable or disable the new router for Heroku Common Runtime applications .
Enable the Router
To use the new router, enable it on your app via a Heroku Labs command:
$ heroku labs:enable http-routing-2-dot-0 -a <app name>
After enabling this flag, the application starts receiving traffic through the new Common Runtime router.
Disable the Router
Disable the flag to stop using the new router. You don't need to do anything else to return your app to its previous routing behavior.
$ heroku labs:disable http-routing-2-dot-0 -a <app name>