# Nix Releases

Published articles for Nix Releases.

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## Nix 2.35.0 released

DevFeed: [Nix 2.35.0 released](<https://devfeed.tech/articles/nix-2-35-0-released-31355.md>)

Original publisher: [Read original article](<https://discourse.nixos.org/t/nix-2-35-0-released/78914>)

Author: lisanna

Published: 2026-07-13T20:36:40Z

Content type: release

Language: en

Sources: [Announcements - NixOS Discourse](<https://devfeed.tech/sources/announcements-nixos-discourse.md>)

Topics: [Nix](<https://devfeed.tech/topics/nix.md>), [releases](<https://devfeed.tech/topics/releases.md>), [content addressed store](<https://devfeed.tech/topics/content-addressed-store.md>), [Security](<https://devfeed.tech/topics/security.md>), [hashing](<https://devfeed.tech/topics/hashing.md>), [integrity](<https://devfeed.tech/topics/integrity.md>)

Tags: [bugfixes](<https://devfeed.tech/tags/bugfixes.md>), [content-addressed-store](<https://devfeed.tech/tags/content-addressed-store.md>), [hashing](<https://devfeed.tech/tags/hashing.md>), [improvements](<https://devfeed.tech/tags/improvements.md>), [integrity](<https://devfeed.tech/tags/integrity.md>), [new-features](<https://devfeed.tech/tags/new-features.md>), [nix-releases](<https://devfeed.tech/tags/nix-releases.md>), [releases](<https://devfeed.tech/tags/releases.md>), [security](<https://devfeed.tech/tags/security.md>)

### AI overview

Nix 2.35.0 is released with new features, bug fixes, performance improvements, and a security fix for recursive-nix. A highlighted change makes source copying to the Nix store more lazy, reducing unnecessary work for typical flake evaluations while preserving the evaluator's existing behavior.

### Source excerpt

On behalf of the Nix team, I am pleased to finally announce the release of Nix 2.35.0. This release contains a good number of new features, bugfixes, and performance improvements, and is available at releases.nixos.org. This release also fixes a security issue with recursive-nix: https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f Release Notes Highlights Sources are copied to the store more lazily #3121 #15711 #15920 Historically, flakes source trees have been eagerly fetched to and evaluated from the Nix store to ensure deterministic and hermetic evaluation, even if the resulting store object is not used as a derivation input. This made the implementation simpler, yet made flakes unusable in large repositories and performed unnecessary writes to the store on each change to the source tree. Since Nix 2.32, all I/O (excluding path: and hg+:-style inputs) for reading sources during evaluation has been funneled to their original filesystem location (or to the ~/.cache/nix/tarball-cache-v2 bare git repository for tarball-based inputs). However, the source tree was still fetched to the store - primarily for computing the resulting content-addressed store path. In most cases, (such as importing the nixpkgs package set) this is not necessary. Touching (and hashing the NAR serialisation of) the whole source tree is unavoidable, since: In case of flake inputs, narHash integrity must be checked eagerly. The outPath attribute of a flake must be known in advance, and for backwards compatibility must be a content-addressed store path string with constant string context representing the flake source tree. Even within the constraints imposed by backwards compatibility requirements, there are several improvements that are achievable. To reduce the number of copies performed, Nix now hashes the input without copying first, assuming that the .outPath will not end up in a derivation attribute and thus would never have to be actually fetched to the store. This comes a