What's new in pip 26.1 – lockfiles and dependency cooldowns

What's new in pip 26.1 - lockfiles and dependency cooldowns! (via) Richard Si describes an excellent set of upgrades to Python's default pip tool for installing dependencies. This version drops support for Python 3.9 - fair enough, since it's been EOL since October. macOS still ships with python3 as a default Python 3.9, so I tried out the new Python version against Python 3.14 like this: uv python install 3.14 mkdir /tmp/experiment cd /tmp/experiment python3.14 -m venv venv source venv/bin/activate pip install -U pip pip --version This confirmed I had pip 26.1 - then I tried out the new lock files: pip lock datasette llm This installs Datasette and LLM and all of their dependencies and writes the whole lot to a 519 line pylock.toml file - here's the result.

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Excerpt limited to ~120 words for fair-use compliance. The full article is at Simon Willison’s Weblog.