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May 2026 Releases

· 5 min read
Ryan Keith
Ryan Keith
Conda Maintainer
Banner image for May 2026 Releases blog post

The May 2026 releases span conda, conda-build, conda-libmamba-solver, conda-pypi, and conda-rattler-solver! 🎉 You'll find them on the main and conda-forge channels.

For conda, lockfiles are a first-class workflow now, the CLI is lighter on everyday commands, and there is more under the hood for channel metadata and future dependency specs. Step-by-step opt-in for beta previews—Rattler and conda-pypi—is on New features to try.

For conda-build, v1 recipes and faster test environments are the highlights.

conda 26.5.0​

Lockfiles without extra tooling. conda export, conda create, and conda install understand conda-lock.yaml and pixi.lock out of the box. Multi-platform locks are supported, and recreating from a lock skips the solver—handy for CI and for sharing exact environments across machines.

A snappier CLI. Startup and initialization are cheaper across the board; even conda -V takes a fast path now. Sharded repodata support also lives in conda core, continuing the push toward more performant searches and solves.

Previews worth watching. The docs page covers two opt-in betas we would love feedback on: the Rattler solver and installing PyPI packages with conda install via the conda-pypi channel. What is stable, what is beta, and how to turn things on are all spelled out on New features to try.

For plugin authors and early adopters. New hooks and knobs include conda_exception_observers and context.preview (opt-in feature previews via config or CONDA_PREVIEW). There is also groundwork in MatchSpec for conditional dependencies and optional groups—building blocks for richer environment specs down the road.

Polish you might notice. Clearer help text around lockfile workflows, warnings when exports miss pip/uv-installed packages, and assorted Windows and PowerShell fixes.

Full changelog: 26.5.0 on GitHub

conda-build 26.5.0​

If you maintain recipes or run conda-build in CI, this release is worth a look.

v1 recipes, conda-build native. Builds for recipe.yaml v1 recipes now go through the py-rattler-build Python API instead of shelling out to the rattler-build CLI.

Faster test environments. The new test_env_template option clones a pre-built template when it exactly matches what a test needs, instead of creating a fresh env from scratch every time.

Allowlist, not whitelist. Recipe keys missing_dso_allowlist and runpath_allowlist are the preferred names now; older *_whitelist keys still work but are headed for removal in 27.3.

Quality-of-life fixes. Windows builds no longer hit WinError 206 on very long command lines; v1 .conda packages can upload to anaconda.org when anaconda_upload is on; and conda_build_config.yaml parsing is quieter when the old numpy warning did not apply.

Full changelog: 26.5.0 on GitHub

conda-libmamba-solver 26.4.1/26.4.2​

  • Cross-platform lockfile export shows the target platform in progress messages; sharded repodata cache uses WAL mode with a longer busy timeout to avoid database is locked errors; add_pip_as_python_dependency is honored again when sharded repodata is enabled.
  • Serializes SQLite cache access through the cache thread to reduce lock contention; configuration guide updates for sharded repodata.

Full changelogs: 26.4.1, 26.4.2

conda-pypi 0.9.0​

conda-pypi has moved out of the conda-incubator.

  • Adds upload timestamps to PyPI metadata conversion; fixes for virtual wheel re-extraction and fn field sourcing from URLs.
  • EXTERNALLY-MANAGED file placement is disabled during the community beta—conda logs an informational notice instead, with plans to re-enable once migration tooling exists.
  • Uses the configured solver backend via the plugin manager rather than hard-depending on conda-rattler-solver.
  • Documentation now covers the conda-pypi channel.

Full changelog: 0.9.0

conda-rattler-solver 0.1.0​

  • First release aligned with conda 26.5—including sharded repodata (v3) support and conditional dependencies / extras in user input.
  • Handles PackagesNotFoundInChannelsError from conda 26.3+.

See New features to try for how to opt in.

Full changelog: 0.1.0

Other releases this month​

A few more projects shipped in May without a deep dive here:

We ❤️ our community​

Thank you to everyone who landed changes across these releases. A special welcome to contributors who contributed for the first time: