Python 2.7, 3.4 and 3.5 are no longer supported
Change effective on 26 September 2022
Python 2.7, 3.4 and 3.5 reached their scheduled upstream end-of-life dates several years ago (see Status of Python Versions), and therefore no longer receive security or bug fixes.
These end-of-life Python versions are only available via the Python buildpack when using the deprecated Heroku-18 stack. As such when Heroku-18 reaches the end of it’s life on April 30th, 2023, further builds (code deployments) using these Python version will no longer be possible.
To raise awareness of this, the Python buildpack has been outputting deprecation warnings in the build log for some time, and as of today the latest version of the Python buildpack now rejects builds using these versions.
Apps should be updated to a supported Python version as soon as possible to keep them secure.