Python 3.13 is now the default Python version
Change effective on 10 December 2024
We have changed the default Python version, used by Python apps that do not specify an explicit Python version, from Python 3.12 to Python 3.13.
For Cedar-generation apps this change does not affect existing apps, since the Python classic buildpack pins the Python version to the same same major Python version as the previous cached build.
For Fir-generation apps this change will affect both new and existing apps the next time you deploy them, since the Python Cloud Native Buildpack does not pin the Python version on rebuilds.
See What’s New In Python 3.13 to learn more about the new Python version.
We strongly recommend that you specify a Python version for your app in a .python-version file instead of relying on the buildpack’s default Python version.