Python 3.6.1 becomes default Python runtime Tuesday, June 20th, 2017

Change effective on 09 June 2017

Effective Tuesday, June 20th, 2017, new Python applications pushed to Heroku will use the python-3.6.1 runtime by default (instead of python-2.7.13).

Existing applications will not be affected by this change.

If you would like to specify Python 2.7, rather than using the new default, please refer to the Heroku Dev Center.