Legacy dynos to be migrated beginning April 3, 2017
Change effective on 03 April 2017
On April 3, 2017, Heroku will begin migrating applications running on paid legacy dynos to current dynos with comparable characteristics.
This migration will not affect any apps created on or after June 15, 2015.
If you created an app before June 15, 2015, read Legacy Dyno Migration Notice to confirm whether this migration will affect it.