You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.

arts
2025.3.31

This version was deleted from PyPI around 2026-05-17. Installing fails with:
$ pip3 install arts==2025.3.31 ERROR: Could not find a version that satisfies the requirement arts==2025.3.31
View other deleted versions of arts

Install through StableBuild

You can install this package from StableBuild's PyPI snapshots from before the version was deleted:
pip3 install \ -i https://YOUR_API_KEY.pypimirror.stablebuild.com/2026-05-16/ \ arts==2025.3.31
Sign up for StableBuild to get an API key (it's free and takes <60 seconds!)

Or, download files manually

And install manually via pip:
arts-2025.3.31-py3-none-any.whl (15.6KB)
arts-2025.3.31.tar.gz (17.3KB)