Python 3.9 support is deprecated
Change effective on 08 January 2025
Python 3.9 is due to reach its scheduled upstream end-of-life in October 2025.
In accordance with our Python Version Support Policy, support for Python 3.9 on Heroku is now deprecated.
Apps using Python 3.9 will continue to build for now, however, a deprecation warning will be shown in the build log.
On 7th January 2026, support for Python 3.9 will be removed from the Python buildpack. Existing Python 3.9 apps will continue to run, however, you will need to upgrade them to a newer version of Python before you can perform any further builds/code deployments.
We recommend upgrading to a newer Python version as soon as possible, to ensure your app both remains secure and can also benefit from the performance and feature improvements found in newer versions of Python.
For more information, see Supported Python Versions.