On behalf of the Python Packaging Authority, I am pleased to announce that we have just released pip 20.3, a new version of pip. You can install it by running `python -m pip install --upgrade pip`.
This is an important and disruptive release -- we explained why in a blog post last year https://pyfound.blogspot.com/2019/12/moss-czi-support-pip.html . We even made a video about it: https://www.youtube.com/watch?v=B4GQCBBsuNU .
Blog post with details: https://pyfound.blogspot.com/2020/11/pip-20-3-new-resolver.html
* **DISRUPTION**: Switch to the new dependency resolver by default. Watch out for changes in handling editable installs, constraints files, and more:
* **DEPRECATION**: Deprecate support for Python 3.5 (to be removed in pip 21.0)
* **DEPRECATION**: pip freeze will stop filtering the pip, setuptools, distribute and wheel packages from pip freeze output in a future version. To keep the previous behavior, users should use the new `--exclude` option.
* Support for PEP 600: Future ‘manylinux’ Platform Tags for Portable Linux Built Distributions.
* Add support for MacOS Big Sur compatibility tags.
The new resolver is now *on by default*. It is significantly stricter and more consistent when it receives incompatible instructions, and reduces support for certain kinds of constraints files, so some workarounds and workflows may break. Please see our guide on how to test and migrate, and how to report issues: https://pip.pypa.io/en/latest/user_guide/#changes-to-the-pip-dependency-reso... . You can use the deprecated (old) resolver, using the flag `--use-deprecated=legacy-resolver`, until we remove it in the pip 21.0 release in January 2021.
In pip 21.0 we will also remove support for Python 2.7.
You can find more details (including deprecations and removals) [in the changelog](https://pip.pypa.io/en/stable/news/), and you can find thank-yous and instructions on reporting issues at https://pyfound.blogspot.com/2020/11/pip-20-3-new-resolver.html .
Thank you, Sumana Harihareswara pip project manager Changeset Consulting https://changeset.nyc