What did the team achieve?​

• Implemented the "SafeClose" feature #2330
• Continued working on partial fanout #1468
• Continued working on chain following approach #2206
• Organised a lovely team off-site!
• Worked on running hydra-node on a Rasberry PI #2353
• Added API to retrieve head start timestamp #2316
• Added blockfrost support to the TUI #2032
• Released version 1.2.0!

What's next?​

• Finish Rasberry PI demo #2353
• Continue working on partial fanout #1468
• Continue work on chain-following improvements #2206
• Tighten up documentation around contestation period #2389
• Add a few more test cases to our HTLC demo

High level summary​

This period Ledger team completed full definion in Haskell and binary representation with CDDL specification of what it means to be a Nested Transaction. Besides this important milestone we've tackled some tech dept, added ability to inject a Cost Model for any Plutus version upon startup for the purpose of testing and benchmarking, optimized memory accounts representation and improved usability of some predicate failures. We made some very nice progress on enhancing CDDL specification with cuddle, which will allow us to reduce quite a bit of code duplication and improve CDDL conformance property testing.

Low level summary​

Features​

• PR-5419 - Type-class-based CDDL generation
• PR-5413 - Subtransactions CBOR deserializer
• PR-5379 - Add ability to inject any cost models via AlonzoGenesis
• PR-5416 - Switch to Credential Staking from RewardAccount in StakePoolState
• PR-5449 - Improve memory representation of ConwayAccountState
• PR-5442 - Deprecate StakeCredential and PaymentCredential synonyms
• PR-5429 - Fail PlutusV4 TxInfo translation when Ptr is present in the TxOuts
• PR-5455 - Make IncompleteWithdrawals more informative
• PR-5457 - Required top level guards
• PR-5441 - Redefine predicate failures in Dijkstra without using CBOR group encoding
• PR-5450 - Remove set-algebra library and all its usage
• PR-5443 - CDDL with typeclasses: mary, alonzo, babbage
• PR-5460 - Ensure EraBlockBody instances are not orphans.
• PR-5451 - Switch to CompactForm Coin in PParams
• PR-5383 - Remove listLenBound from EncCBORGroup class

Testing​

• PR-5426 - Test "accepted" predicates in conformance
• PR-5434 - Add Imp test reproducer for #5418
• PR-5433 - Make ticking a bit more realistic in Imp tests
• PR-5440 - Bump constrained-generators

Infrastructure and releasing​

• PR-5445 - Fix cddl generation
• PR-5462 - Fix codegen

High level overview​

This week, the Mithril team kept focusing on the SNARK-friendly STM library, completing the Schnorr signature scheme and modules reorganization, and implementing some wrappers for the Jubjub backend. They also progressed on specifying the non-recursive SNARK circuit, assessing constraints on Halo2 verification keys, prototyping the recursive SNARK solution, and prototyping the Bitcoin DeFi prover with RISC Zero.

Additionally, they continued implementing a simple aggregator discovery mechanism, worked on improvements to the protocol security page, and completed enhancements to the end-to-end tests to better support the introduction of new features and improve the reliability of the backward-compatibility test.

Finally, they worked on the second phase of the common aggregator client implementation and kept upgrading to Cardano node v.10.6.

Low level overview​

Features​

• Completed the issue Implement Schnorr signature scheme in STM #2756
• Completed the issue Re-organize modules of STM library #2793
• Worked on the issue Implement a simple aggregator discovery mechanism #2726
• Worked on the issue Experimental blst-Jubjub #2772
• Worked on the issue Compute the IVC state with SHA256 in the recursive circuit #2806
• Worked on the issue Document recursive SNARK solution #2767
• Worked on the issue Prepare specifications for the Mithril circuit #2797
• Worked on the issue Implement Jubjub/Poseidon backends wrappers in Schnorr signature scheme #2817
• Worked on the issue Assess constraints on Halo2 circuit verification #2799
• Worked on the issue Feasibility of Bitcoin Defi usecase #2818
• Worked on the issue Update protocol parameters to SNARK friendly values #2813
• Worked on the issue Proposals for Mithril/DMQ as optout feature of Cardano #2831

Protocol maintenance​

• Completed the issue Certification stopped on mainnet and preview network #2805
• Completed the issue Enhance e2e test to support the introduction of new features #2781
• Completed the issue Enhance reliability of backward compatibility test #2760
• Completed the issue Stabilize Cardano DB v2 client CLI/library - Phase 4 #2758
• Completed the issue Revise expiration delays for signed entity types #2826
• Worked on the issue Enhance protocol security page on website #2703
• Worked on the issue Upgrade to Cardano 10.6 #2790
• Worked on the issue Implement a common aggregator client - Phase 2 #2827

High-level summary​

• Release testing: Node 10.5.2, 10.5.3, 10.6.0, and 10.6.1.
• Development: Ongoing testing framework improvements.
• Maintenance: Analysis and fixes for nightly job failures.

Low-level overview​

Release testing​

We tested the 10.5 point releases. These contained only bug fixes, so previous test coverage largely applied. We focused on regression testing on local testnets and found no issues.

We also tested the 10.6.0 and 10.6.1 releases and produced a test report. During testing we found and reported two issues:

• BUG – cardano-cli queries hang indefinitely with the V1LMDB backend: issue #1787
• BUG – ObsoleteNode and no blocks forged on PV11: issue #6382

Our Node build test also uncovered an issue in the build documentation, and we submitted a fix PR.

Development​

Over the past two weeks, we enabled testing for Node 10.6. We updated our testnet setup for the new Dijkstra genesis file and disabled legacy and mixed topologies, as legacy topology is no longer supported in 10.6.

We also improved our test framework by adding timeouts for key operations:

• Obtaining a testnet cluster instance
• Calling cardano-cli
• Entire test run
• Network requests

Issue #1787 caused tests to hang indefinitely on cardano-cli commands, so adding these timeouts was essential.

Maintenance​

We continued analyzing and fixing nightly job failures. We are currently maintaining a 100% success rate with no flaky tests.

High level summary​

• Participated in the November 2025 incident response, providing analysis on potential intervention scenarios and tracking chain progression metrics.
• Merged documentation of the Leios Protocol Burst attack threat model (ouroboros-leios#624), strengthening the protocol's security foundation ahead of load testing and mitigation strategy development.
• Continued preparation for the Leios November demo, with significant progress on observability infrastructure using Grafana and Prometheus (#1766), and demo packaging to streamline deployment (#1759). Both tasks are expected to be completed by end of week.