What's new in pip 26.1 - lockfiles and dependency cooldowns!
- 新增 lockfiles 功能，生成精确依赖锁定文件 pylock.toml。
- 支持依赖冷却选项 --uploaded-prior-to，避免安装过于新版本。
- 停止支持 Python 3.9，建议升级到更高版本。
What's new in pip 26.1 - lockfiles and dependency cooldowns!
[Simon Willison’s Weblog](http://simonwillison.net/)
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28th April 2026 - Link Blog
**What's new in pip 26.1 - lockfiles and dependency cooldowns!** ([via](https://lobste.rs/s/w2oiaq/what_s_new_pip_26_1_lockfiles_dependency "Lobste.rs")) 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 --versionThis confirmed I had `pip 26.1` - then I tried out the new lock files:
pip lock datasette llmThis 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 --versionThis gave me version 0.30.
Posted 28th April 2026 at 5:23 am
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This is a **link post** by Simon Willison, posted on 28th April 2026.
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