Change effective on 12 January 2016
To help improve platform stability, a new per-application dyno limit has been added. By default, applications are now limited to 100 dynos total (regardless of size or process type). Applications using more than this at the time the change went into effect have had the limit raised.
If your application requires more dynos than this, please contact support by opening a ticket and we’ll be happy to raise the limit.
You can read more about Heroku platform limits here.