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November 2025 Releases

· 4 min read
Ken Odegard
Ken Odegard
Conda Maintainer
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The November 2025 releases included updates to conda, conda-build, and conda-libmamba-solver! 🎉 All of these have been released to both defaults and conda-forge channels.

Special Announcement

This release includes preliminary support for fetching CEP 16 sharded repodata, a substantially more efficient way of distributing the necessary metadata to install packages in your environments. Read more about it in our sharded repodata blog post.

You can try it out by following these steps:

  • Update to conda-libmamba-solver 25.11.0 or later
  • Enable it in your settings: conda config --set plugins.use_sharded_repodata true
  • Set this environment variable: CONDA_PLUGINS_USE_SHARDED_REPODATA=1

Note that sharded repodata requires that the target channels expose the necessary metadata, too, so it will only work with CEP-16-ready deployments. conda-libmamba-solver will fall back to non-sharded/monolithic repodata if not available, so you can mix sharded and non-sharded channels.

This feature is only available when using conda-libmamba-solver 25.11.0 and later and is not implemented in the classic solver.

Changes in conda 25.11.0​

To update conda to the latest version, run:

conda install --name base conda=25.11.0

Notable Changes:

  • Enhanced virtual packages plugin API with new fields for controlling override behavior.
  • Added new override_virtual_packages (alias: virtual_packages) configuration key to .condarc for overriding virtual package versions and build numbers.
  • Added created and last_modified properties to conda environments.
  • Added new envs_details field to conda info --json output for inspecting properties of registered environments (also available via conda info --envs --json and conda env list --json).
  • Fixed various bugs related to MatchSpec serialization, channel URL handling, and Python 3.14 compatibility.
  • Improved warning for users attempting to add reserved environment variables like PATH to environment configurations.

Check out the full changelog for more: 25.11.0

Changes in conda-build 25.11.0​

To update conda-build to the latest version, run:

conda install --name base conda-build=25.11.0

Notable Changes:

  • Added support for specifying a custom PyYAML loader when parsing configuration files via conda_build.variants.parse_config_file.
  • Fixed BUILD environment variable to properly respect the cdt_name variant configuration. Previously, it was hardcoded to use cos6 or cos7 based on architecture.
  • Fixed Windows MSVC version detection for Python 3.5+.
  • Updated CMake generator handling for CMake 4 compatibility (CMake 2 support was dropped in CMake 4).
  • Python 3.9 support has been removed. The minimum supported Python version is now 3.10.

Check out the full changelog for more: 25.11.0

Changes in conda-libmamba-solver 25.11.0​

To update conda-libmamba-solver to the latest version, run:

conda install --name base conda-libmamba-solver=25.11.0

Notable Changes:

  • Added experimental support for CEP 16 sharded repodata (see announcement above).
  • Added support for CEP 17 python_site_packages_path.
  • Fixed the cpuonly mutex to correctly prevent CUDA packages from being installed, matching classic solver behavior.
  • Added new messaging for when conda is outdated, environment is frozen, and conda-self is installed.
  • Python 3.9 support has been dropped. The minimum supported Python version is now 3.10.
  • Added codspeed benchmarking GitHub action and benchmarks.

Check out the full changelog for more: 25.11.0

We ❤️ Our Community​

Altogether, we had 7 new contributors this release cycle; thank you to all of our open source community members for helping make these improvements possible.