Change effective on 24 October 2013
Dynos running on Heroku are cycled at least once per day. We are rolling out a change that makes the switch from old to new dyno smoother: Instead of waiting for the old dyno to shut down before starting a new one, Heroku now starts the new dyno as soon as the shutdown signal is sent to the old dyno. This change brings daily dyno restart behavior in line with general restart behavior and restart behavior when new app releases are deployed.
Read more about the Heroku Dyno Manager on Dev Center.