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

delta-core
1.2.5

This version was deleted from PyPI around 2025-10-24. Installing fails with:
$ pip3 install delta-core==1.2.5 ERROR: Could not find a version that satisfies the requirement delta-core==1.2.5
View other deleted versions of delta-core

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/2025-10-23/ \ delta-core==1.2.5
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Or, download files manually

And install manually via pip:
delta_core-1.2.5-py3-none-any.whl (53.0KB)
delta_core-1.2.5.tar.gz (48.2KB)