[benjaminguttmann-avtq]

Thanks for contributing to the buildpack. To speed up the process of reviewing your pull request please provide us with:

• A short explanation of the proposed change:

  • Drop EOL Python 3.10 + CFLinuxFS3.
  • Switch Default to Python 3.14

• An explanation of the use cases your change solves

• I have viewed signed and have submitted the Contributor License Agreement

• I have made this pull request to the master branch

• I have added an integration test

[Copilot]

🔵 Needs a closer look

The default-runtime jump from Python 3.10 to 3.14 affects all unpinned applications, and native-dependency and monitoring-agent compatibility requires staging, integration, and BRATS validation unavailable in this review.

No open issues 🎉

What changed in this PR

This PR retires Python 3.10 and cflinuxfs3 support from the Python buildpack and makes Python 3.14 the default runtime. It also updates test fixtures and documents the migration impact for applications.

Changes:

• Remove Python 3.10 and cflinuxfs3 dependencies from the manifest.
• Update integration settings, runtime expectations, and fixture dependencies for Python 3.14.
• Document the default-runtime change and stack migration requirements.

File	Description
src/​python/​integration/​versions_test.go	Test explicit Python 3.14 runtime selection.
src/​python/​integration/​init_test.go	Default integration tests to cflinuxfs4.
src/​python/​brats/​brats_test.go	Remove cflinuxfs3-specific database error expectations.
manifest.yml	Remove retired dependencies and default to Python 3.14.
fixtures/​vendored/​transitive/​runtime.txt	Select Python 3.14.
fixtures/​vendored/​transitive/​requirements.txt	Refresh transitive-dependency fixture packages.
fixtures/​vendored/​simple/​requirements.txt	Refresh vendored application dependencies.
fixtures/​vendored/​pipenv/​Pipfile.lock	Update locked dependencies and Python requirement.
fixtures/​vendored/​pipenv/​Pipfile	Update package pins and select Python 3.14.
fixtures/​util/​override_buildpack/​override.yml	Remove cflinuxfs3 from the override fixture.
fixtures/​services/​sealights/​requirements.txt	Update Flask in the SeaLights fixture.
fixtures/​services/​appdynamics/​requirements.txt	Update application dependencies and AppDynamics agent.
fixtures/​pipenv/​Pipfile.lock	Update locked dependencies and Python requirement.
fixtures/​pipenv/​Pipfile	Update package pins and select Python 3.14.
fixtures/​miscellaneous/​hooks/​requirements.txt	Update Gunicorn in the hooks fixture.
CHANGELOG	Document runtime and stack migration requirements.

_{Review effort: Balanced}