v284

• Fixed parsing of runtime.txt and .python-version files that contain CRLF characters. (#1789)

v283

• Added a warning when an app doesn't specify a Python version and instead relies upon the default/cached version. (#1787)
• Improved the instructions for migrating from runtime.txt to .python-version. (#1783)
• Improved the error messages shown when .python-version, runtime.txt or Pipfile.lock contain an invalid Python version. (#1783 and #1786)
• Improved the rendering of the error message shown when .python-version or runtime.txt contain stray invisible characters (such as ASCII control codes). (#1783)
• Improved the upgrade instructions shown for EOL and unsupported Python versions. (#1783 and #1786)
• Improved the error messages shown when no Python package manager files are found. (#1787)

v282

• Removed support for Heroku-20. (#1778)

v281

• The Python 3.13 version alias now resolves to Python 3.13.3. (#1775)
• The Python 3.12 version alias now resolves to Python 3.12.10. (#1775)
• The Python 3.11 version alias now resolves to Python 3.11.12. (#1775)
• The Python 3.10 version alias now resolves to Python 3.10.17. (#1775)
• The Python 3.9 version alias now resolves to Python 3.9.22. (#1775)

v280

• Updated pip from 24.3.1 to 25.0.1. (#1759)
• Updated Poetry from 2.1.1 to 2.1.2. (#1772)

v279

• Updated Poetry from 2.0.1 to 2.1.1. (#1758)
• Stopped filtering out pip's Requirement already satisfied: log lines when installing dependencies. (#1765)
• Improved the error messages shown if installing pip/Poetry/Pipenv fails. (#1764)
• Stopped installing pip into Poetry's virtual environment. (#1761)

v278

• Added build-time rewriting of editable VCS dependency paths (in addition to the existing run-time rewriting), to work around an upstream Pipenv bug with editable VCS dependencies not being reinstalled correctly for cached builds. (#1756)
• Changed the location of repositories for editable VCS dependencies when using pip and Pipenv, to improve build performance and match the behaviour when using Poetry. (#1753)

v277

• Improved the warning message shown when the requested Python version is not the latest patch version. (#1749)
• Improved the error message shown when the requested Python patch version isn't available. (#1749)
• Improved the error message shown if there was a networking or server related error downloading Python. (#1749)
• Adjusted the curl options used when downloading Python to set a maximum download time of 120s to prevent hanging builds in the case of network issues. (#1749)
• Refactored the Python download step to avoid an unnecessary version check HEAD request to S3 prior to downloading Python or reusing a cached install. (#1749)
• Updated the runtime.txt deprecation warning to include a link to the deprecation changelog post. (#1747)
• Improved buildpack metrics for Python version selection. (#1749)
• Improved buildpack metrics for builds that fail. (#1746 and #1749)

v276

• The Python 3.13 version alias now resolves to Python 3.13.2. (#1744)
• The Python 3.12 version alias now resolves to Python 3.12.9. (#1744)
• Deprecated support for the runtime.txt file. (#1743)
• Improved the error messages shown when .python-version, runtime.txt or Pipfile.lock contain an invalid Python version. (#1743)

v275

• Updated Poetry from 1.8.5 to 2.0.1. (#1734)