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Aztec

Noir 1.0, the language behind Aztec contracts, reaches its first stable release

Aztec released Noir 1.0 on 29 October 2026, promising no breaking changes across the 1.x series. Aztec.nr will target Noir 1.0 with Aztec v6, so contract developers on v5 need to migrate their toolchain.

Aztec announced on 29 October 2026 that Noir 1.0, the first stable release of its open-source language for zero-knowledge programs, is live. Noir is the language that Aztec smart contracts are written in, through the Aztec.nr framework, so the release matters mainly to builders on the network.

What changed

The release adds no new language features. It is about stability. According to Aztec's announcement:

  • Stable language. Syntax and semantics are meant to hold across the whole 1.x series. Aztec writes: "Breaking changes will require a major version, with a deprecation period and migration guidance."
  • Versioned toolchain. nargo follows semantic versioning, and noirup installs and pins versions.
  • Stable intermediate representation. ACIR, the format that proving backends such as Barretenberg consume, now offers a consistent interface for integrations.
  • Clearer execution boundaries. The split between constrained code (ACIR, which is proven) and unconstrained code (Brillig) is better defined, so developers can see what has to be verified inside a proof.

Aztec says the compiler and toolchain went through internal and external security reviews, along with fuzz testing and bytecode verification, since the first 1.0 pre-release in December 2024. It positions the release for production use.

What it means for builders

  • Noir developers should upgrade with noirup and follow the migration guide for changes between their current version and 1.0.
  • Aztec contract developers are affected through Aztec.nr, which targets Noir 1.0 with Aztec v6. Aztec said developers on v5 should move to the updated toolchain with v6 and pointed to its documentation for instructions. Aztec v6 has since become the canonical rollup on mainnet (see BitBasic's earlier post: https://bitbasic.com/news/2-aztec-v6-is-live-on-mainnet-as-the-new-canonical-rollup).

Sequencers and delegators

The announcement asks nothing of node operators, and it does not change staking or rewards. Sequencers should still be on the v6 node release described in BitBasic's v6 post. The sequencer set, epochs and governance are tracked at https://bitbasic.com/aztec.

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