> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dfns.co/llms.txt
> Use this file to discover all available pages before exploring further.

# MPC signer

> Release notes for the DFNS MPC signer: protocol updates, security fixes, and operational improvements.

Current release: **v2.17.0**.

<Update label="v2.17.0" tags={["Security", "Operational"]}>
  *January 20th, 2026*

  **Security:**

  * Updated to the released `cggmp24` crate including an upstream security fix.

  **Operational:**

  * IBM Z (s390x) architecture support added for signer builds.
  * Key import/export WASM module updated to the latest revision (remains compatible with the prior format).
  * Removed deprecated MAC options and stray `gmp` dependency; `cggmp` backend is now selectable via a build feature.
</Update>

<Update label="v2.16.3" tags={["New Feature", "Protocol", "Security"]}>
  *October 28th, 2025*

  **Protocol:**

  * Migrated to **cggmp24**. The signing protocol previously referenced as `cggmp21` has been renamed and upgraded to its latest revision. Reference implementations of components used in this upgrade are published through the [Hyperledger Lockness](https://github.com/LFDT-Lockness/cggmp21) project.
  * ECDSA pre-signatures can no longer be used with HD derivation or raw signing.
  * Stark signing is now rejected at signer initialization.

  **Key import/export:**

  * `KeyImportResponse` now includes the chain code for HD-derived keys.
  * Key import/export remains compatible with the prior WASM module format.

  **Operational:**

  * HD wallet support added to KU23 full signing.
  * Replay protection re-enabled on signing requests.
  * Incoming client certificates are verified to match the server's organization. Subject CN check is optional and configurable.
  * New CLI option to disable client cert verification.
  * Build base updated to Rust 1.89.
</Update>

<Update label="v2.14.3" tags={["Bug Fix"]}>
  *August 13th, 2025*

  **Protocol:**

  * Patched `cggmp21` dependency.
</Update>

<Update label="v2.14.2" tags={["Operational", "Security"]}>
  *July 25th, 2025*

  **Healthcheck:**

  * Healthcheck server migrated to HTTP, with shared cert validity and HTTP response helpers.
  * CA cert validity is now also checked.

  **Operational:**

  * Migration scripts added with automatic migration number deduction.
  * Build base updated to Rust 1.88 / Rust 2024 edition.
  * S3 bucket uploads now always compute the checksum.
</Update>

<Update label="v2.14.0" tags={["New Feature", "Operational"]}>
  *May 21st, 2025*

  **Storage:**

  * Postgres support added with a Postgres fallback.
  * Redis dependency removed.

  **Signing:**

  * HD derivation enabled for EdDSA keys.
  * Key import/export: FrostBitcoin support added.

  **Operational:**

  * New key rotation subcommand.
  * tDH (threshold Diffie–Hellman) implementation added, with a new key share type.
</Update>

<Update label="v2.13.2" tags={["New Feature", "Operational"]}>
  *January 24th, 2025*

  **Backup & restore:**

  * L4 backup support introduced. L4 backup can be enabled independently of L3.
  * New backup restore CLI tool with batched, multi-phased operations.
  * Backup keys can now be read from OpenSSL PEM-DER files.
  * Backup restore output can be emitted in hex format.

  **Telemetry:**

  * W3 Tracing Context propagation across services.
  * Span instrumentation added to SQL queries, delivery handshake, and secrets manager operations.
  * Resource attributes can be overridden via OTel exporter config.
</Update>

<Update label="v2.12.1" tags={["New Feature", "Operational"]}>
  *September 30th, 2024*

  **Signing:**

  * Bitcoin Schnorr: HD derivation and taproot support added.
  * KU23 pre-signatures batching introduced for higher throughput.
  * Stark pre-signatures added.
  * KU23 pre-signatures are now insensitive to participant identity ordering.

  **Cluster operations:**

  * Added the ability to copy key shares to a smaller cluster.
  * Cluster info is now required for commands that previously assumed cluster awareness.
  * Removed the standalone `generate` command — keys are now generated on startup (configurable via feature flags).
  * Added a `get-public-identity` subcommand.

  **Reliability:**

  * Graceful shutdown on SIGINT/SIGTERM.
  * TLS key handling and dev-cert flows reworked.

  **Telemetry:**

  * New `TRACECONTEXT_PROPAGATORS_HEADER` setting.
</Update>

<Update label="v2.11.2" tags={["Initial Release"]}>
  *July 17th, 2024*

  First release of the MPC Clusters signer tracked in this changelog.
</Update>