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June 2025

· 5 min read
Jean-Philippe Raynaud
Noon van der Silk
Sebastian Nagel

This is a monthly report on the progress of 🐲 Hydra and 🛡 Mithril projects since June 2025. It serves as preparation for, and a written summary of, the monthly stakeholder review meeting. The meeting is announced on our Discord channels and held on Google Meet. This month, the meeting took place on June 25, 2025, using these slides, and you can see the recording here.

Mithril​

Issues and pull requests closed in June

Roadmap​

Below are the latest updates on our roadmap:

  • DMQ signature diffusion prototype #2402. We have started the second phase of the implementation of the DMQ signature diffusion prototype
  • Redesign the website and improve documentation #2051. The new home page has been deployed on the website
  • Refactor STM library #2567. We have completed the first phase of the refactoring of the SMT library, and we have started the second phase.

Distributions​

In June, we have completed the following events:

  • Released the new distribution 2524
  • Activated support for UTXO-HD in the Mithril client CLI
  • Prepared for the switch to the new Cardano database certification backend.

In July, the following events are planned:

  • Release of a new distribution (2529).

Dev blog​

We have published the following post:

New website homepage​

We launched a redesigned homepage with a modern look, improved navigation, and better accessibility.

The new homepage

Snapshot of the new homepage

DMQ implementation update​

Here is the current status of the DMQ implementation:

Mini-protocolsPallasMithril SignerMithril AggregatorHaskell DMQ Node
N2C Submission✓✓-In progress
N2C Notification✓-✓In progress
N2N Diffusion---In progress

Next, we will complete an end to end test with a fake DMQ node and gradually replace it with the real Haskell DMQ node implementation. Our goal is to operate the DMQ network on a testnet.

Cardano database certification backend update​

The Cardano node database v2 certification offers incremental verification and greater efficiency compared to the original method. It will progressively replace the current certification process for the Cardano node internal database.

In particular, the cardano-db command in the Mithril client CLI has been updated to support the new incremental certification process and eventually a seamless switch to the new backend. A new --backend option has been added to the command, allowing users to specify the certification version:

  • --backend v1 uses the original Cardano node database certification (this remains the default)
  • --backend v2 enables the new incremental Cardano node database certification.

We will progressively switch to the new backend in the coming months, a full schedule is available in this blog post: Switching to Cardano database incremental certification.

UTxO-HD ledger state snapshot converter command in client CLI​

With the release of the new 2524 distribution, the tools command has been added to the Mithril client CLI. The new tools utxo-hd snapshot-converter subcommand simplifies node bootstrapping by converting the restored ledger state snapshot into the required UTxO-HD flavor (LMDB or Legacy).

The following command can be used to convert a restored ledger state snapshot into the UTXO-HD flavor:

./mithril-client --unstable tools utxo-hd snapshot-converter --db-directory $DB_DIRECTORY --cardano-node-version 10.1.4 --utxo-hd-flavor $UTXO_HD_FLAVOR --cardano-network $CARDANO_NETWORK

More information is available in the UTXO-HD ledger state snapshot converter command in client CLI dev blog post.

Verify existing Cardano database with client CLI​

We have created a new command in the Mithril client CLI to verify an existing Cardano database. This command allows users to check the integrity of their Cardano node database and ensure it is authentic. The tool has not been released yet, but it is available in the unstable release of the Mithril client CLI.

Here is an example of how to use the command:

./mithril-client --unstable cardano-db verify --db-directory $DB_DIRECTORY

Protocol status​

The protocol operated smoothly on the release-mainnet network with the following metrics:

  • Registered stake: 4.7B₳ (21% of the Cardano network)
  • Registered SPOs: 247 (9% of the Cardano network)
  • Full Cardano database restorations: 185 restorations
  • Signer software adoption: 81.1% of the SPOs are running a recent version (one of the last three releases).

You can find more information on the Mithril protocol insights dashboard.

Hydra​

Issues and pull requests closed in June

The roadmap with features and ideas

Snapshot of the new roadmap with features and ideas

This month, notable roadmap updates include:

0.22.0 Release​

  • Important security fix for security advisory: Dangerous L1 event finality assumptions and Failed transactions not considered
  • Event log rotation feature; --persistence-rotate-after 10000 to rotate after seeing 10k events
  • The etcd binary is now embedded into the binary, and used by default Disable with --use-system-etcd
  • New /head HTTP endpoint to get status of the head
  • UX improvements to diagnose etcd connection problems.

New working group​

Hydra working group → Layer 2 working group!

More details here: wg-layer2.

Roadmap update​

  • We are focused on supporting the Glacier Drop, and are working on improving our failure resilience
  • We are also working on improving the UX around etcd/networking errors
  • We are aiming to implement a HTLC between Hydra heads, to form a pathway to Bitcoin lightning integration.

The monthly review meeting for June 2025 took place on June 25, 2025, via Google Meet. The presentation slides and the recording are available for review.