Quoting Seth Larson

Simon Willison's Blog News

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PyPI now rejects uploads of new files to releases older than 14 days to prevent supply-chain attacks, a proactive security measure announced by Seth Larson.

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# A quote from Seth Larson Source: [https://simonwillison.net/2026/Jul/23/seth-larson/](https://simonwillison.net/2026/Jul/23/seth-larson/) 23rd July 2026 > The Python Package Index \(PyPI\) now rejects new files being uploaded to releases that are older than 14 days\. This restriction was[put in place](https://github.com/pypi/warehouse/pull/19727)to prevent old and long\-stable releases from being poisoned in case publishing tokens or workflows of PyPI projects were compromised\. As far as we are aware this has not yet been abused, but there is no technical reason beyond that attackers weren't aware it was possible\. —[Seth Larson](https://blog.pypi.org/posts/2026-07-22-releases-now-reject-new-files-after-14-days/),PyPI blog

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PyPI releases now reject new files after 14 days

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PyPI now rejects new file uploads to releases older than 14 days, a security measure to prevent supply chain attacks by compromising old releases. The change was driven by incidents like the LiteLLM and Telnyx compromises.