What’s new in pip 26.1 – lockfiles and dependency cooldowns!

What’s new in pip 26.1 – lockfiles and dependency cooldowns!

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.

The new release also supports dependency cooldowns, discussed here previously, via the new --uploaded-prior-to PXD option where X is a number of days. The format is P-number-of-days-D, following ISO duration format but only supporting days.

I shipped a new release of LLM, version 0.31, three days ago. Here’s how to use the new --uploaded-prior-to P4D option to ask for a version that is at least 4 days old.

pip install llm --uploaded-prior-to P4D
venv/bin/llm --version

This gave me version 0.30.

Via Lobste.rs

Tags: packaging, pip, python, security, supply-chain

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