Sourced from pip's changelog.

21.0 (2021-01-23)

Deprecations and Removals

• Drop support for Python 2. (#6148)
• Remove support for legacy wheel cache entries that were created with pip versions older than 20.0. (#7502)
• Remove support for VCS pseudo URLs editable requirements. It was emitting deprecation warning since version 20.0. (#7554)
• Modernise the codebase after Python 2. (#8802)
• Drop support for Python 3.5. (#9189)
• Remove the VCS export feature that was used only with editable VCS requirements and had correctness issues. (#9338)

Features

• Add --ignore-requires-python support to pip download. (#1884)
• New resolver: Error message shown when a wheel contains inconsistent metadata is made more helpful by including both values from the file name and internal metadata. (#9186)

Bug Fixes

• Fix a regression that made pip wheel do a VCS export instead of a VCS clone for editable requirements. This broke VCS requirements that need the VCS information to build correctly. (#9273)
• Fix pip download of editable VCS requirements that need VCS information to build correctly. (#9337)

Vendored Libraries

• Upgrade msgpack to 1.0.2.
• Upgrade requests to 2.25.1.

Improved Documentation

• Render the unreleased pip version change notes on the news page in docs. (#9172)
• Fix broken email link in docs feedback banners. (#9343)

20.3.4 (2021-01-23)

Features

• pip wheel now verifies the built wheel contains valid metadata, and can be installed by a subsequent pip install. This can be disabled with --no-verify. (#9206)
• Improve presentation of XMLRPC errors in pip search. (#9315)

Bug Fixes

• Fixed hanging VCS subprocess calls when the VCS outputs a large amount of data on stderr. Restored logging of VCS errors that was inadvertently removed in pip 20.2. (#8876)

... (truncated)

• 6c09bdd Bump for release
• 2a6f3c6 Fix syntax of classifiers
• f030515 Revert "Bump for release"
• e01c7d7 Revert "Bump for development"
• 69cfa8e Merge pull request #9496 from pfmoore/release_21.0
• c1382e9 Bump for development
• 91f43f1 Bump for release
• 5575209 Update AUTHORS.txt
• a27d06e Merge pull request #9495 from pradyunsg/update-to-include-20.3.4
• 8517a44 Update changelog for 20.3.4
• Additional commits viewable in compare view

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