High level summary​

This update covers a longer stretch than usual because there was no report since 2026-05-27: the whole Ledger team was first at the ZuriHac conference and then had an in-person team meetup, so the last several weeks were lighter on routine reporting but no less productive. A good chunk of the work below is the continuation of storylines from earlier updates, alongside a few new fronts.

On the performance side the state-annotated transaction (StAnnTx) work reached back to the older eras. Integration of the memoized values held in StAnnTx had previously been done for Babbage onward, and this cycle it was extended to Alonzo, which needed special handling, along with a small follow-up removing an unnecessary EncCBOR instance for AlonzoStAnnTx. We also finished the long-running effort to remove the legacy Coders machinery: the final piece for protocol version 12 and up (dropping the Summands usage) landed, Coders was removed from the testlibs and tests, and StakePoolParams was switched from CBORGroup-derived encoding to manual EncCBOR/DecCBOR instances in preparation for dynamic CBOR list lengths.

A notable new front is Leios support beginning to land in the ledger. The LeiosCert type, defined in the new cardano-crypto-leios package on the cardano-base repository, was added as an optional field to DijkstraBlockBody, and the Dijkstra CDDL for header_body was updated to reflect what the Leios prototype should be producing. We also introduced a new cardano-protocol package to house protocol-level code. On the ledger rules themselves there was a round of structural cleanup: a new ENTITIES rule (with an equivalent subrule) was introduced between LEDGER and CERTS to handle withdrawals and direct deposits, the era prefix was dropped from rule names, and the Rewarding script purpose was renamed to the more accurate Withdrawing.

The Dijkstra era work continued on several smaller fronts, including requiring top-level guards in the top-level transaction body, adjusting the Conway transaction_witness_set CDDL rule to use non-empty lists for the relevant fields. Conformance testing for Dijkstra advanced to its third installment, this time adding SpecTranslate instances for Dijkstra types and ExecSpecRule instances for the LEDGER and NEWEPOCH rules. Two user-visible bugs were fixed: injected extraConfig cost models were being ignored for PlutusV1/V3 because of an argument-ordering issue in overrideCostModels, and TxInfo translation could fail spuriously in LegacyMode. We also added ToJSON/FromJSON instances for EraScript and native scripts.

On the tooling and infrastructure side the generate-cbor CLI tool added last cycle was moved into cardano-ledger-api, refactor of the singleton-key namespaces (committee and constitution) for Canonical Ledger State, new Conway UTxO and Script generators were added, and CI was updated to allow automated agents to invoke the /update-changelogs skill. The dependency stack was moved forward with updates to cardano-crypto-class-2.5, the haskellNix flake input, and the usual GitHub Actions bumps.

Low level summary​

Features​

• PR-5837 - Remove unnecessary re-exports from Shelley Rules
• PR-5859 - Remove era prefix from rule names
• PR-5748 - Refactor namespaces with singleton keys
• PR-5867 - Prevent TxInfo translation failure for LegacyMode
• PR-5866 - Rename Rewarding to Withdrawing
• PR-5845 - Add ToJSON/FromJSON instances for EraScript
• PR-5860 - Stop using Summands from Coders for PV12+
• PR-5857 - Further StAnnTx integration
• PR-5872 - Add LeiosCert to DijkstraBlockBody
• PR-5897 - Remove unnecessary EncCBOR instance for AlonzoStAnnTx
• PR-5899 - Fix injected extraConfig cost models being ignored for PlutusV1/V3
• PR-5878 - Entities and Subentities Rules
• PR-5889 - Fix Dijkstra CDDL for Leios changes to header_body
• PR-5887 - Create cardano-protocol package
• PR-5903 - Require top-level guards in top-level transaction body
• PR-5908 - Use non-empty list for fields without duplicate enforcement in Conway transaction_witness_set cddl rule
• PR-5890 - Replace CBORGroup-derived EncCBOR/DecCBOR for StakePoolParams with manual instances

Testing​

• PR-5844 - Prepare conformance for Dijkstra 3
• PR-5868 - Add Test.Cardano.Ledger.Conway.Gen.{UTxO,Script} modules.
• PR-5883 - Add isPotentialFutureMember ImpTest

Infrastructure and releasing​

• PR-5864 - Move generate-cbor to cardano-ledger-api
• PR-5870 - Update to cardano-crypto-class-2.5
• PR-5876 - Bump actions/checkout from 6 to 7 in the actions group
• PR-5877 - Allow agents to invoke /update-changelogs
• PR-5865 - Remove Coders from testlibs and tests
• PR-5884 - Bump actions/cache from 5 to 6 in the actions group
• PR-5894 - Update haskellNix flake input

High level overview​

This week, the Mithril team refactored the unsafe SNARK setup, prepared the prover input for the recursive SNARK aggregation primitives, decoupled the Midnight library in the SNARK recursive circuit, and tested that the degree of the SNARK circuits remains unchanged. They continued improving the modularity of the SNARK recursive circuit using gadgets.

The team also worked on enhancing the aggregator state machine to support the Blocked state and on capturing end-to-end execution logs in artifacts.

Finally, they continued work on shipping the Mithril signer node binary in the Cardano node bundle, releasing the 2628 distribution, upgrading the Cardano node to 11.1, updating the DMQ node to 0.7.0.0, and upgrading the midnight-zk library to 2.3.3.

Low level overview​

Features​

• Completed the issue Refactor unsafe SNARK setup #3300
• Completed the issue Recursive SNARK aggregation primitives: Refactor preparation of prover input #3319
• Completed the issue Refactor SNARK recursive circuit - Midnight library decoupling #3129
• Completed the issue Test that SNARK circuits degree are unchanged #3330
• Worked on the issue Refactor SNARK recursive circuit - Modularity enhancement with gadgets #3131

Protocol maintenance​

• Worked on the issue Ship Mithril signer node binary in Cardano node bundle in GitHub #3011
• Worked on the issue Release 2628 distribution #3271
• Worked on the issue Enhance aggregator state machine to support Blocked state #3333
• Worked on the issue Upgrade to Cardano 11.1 #3346
• Worked on the issue Update DMQ node to 0.7.0.0 #3358
• Worked on the issue Capture e2e execution logs in artifacts #3362
• Worked on the issue Upgrade midnight-zk to 2.3.3 #3375

High level summary​

In the past weeks, the Plutus team has continued to make improvements across performance, tooling, and assurance.

Performance and compiler improvements. We improved several parts of the Plutus optimization pipeline and ledger API implementation. This includes making common Value operations more efficient, adding a new compiler optimization for certain recursive functions, and fixing an optimization pass so that it preserves program behavior correctly.

Better benchmarking and tooling. We added lightweight benchmarking support to the uplc executable, making it easier to sanity-check execution-time measurements for UPLC scripts and compare results against existing benchmark infrastructure.

Specs and formal methods. We continued strengthening the foundations of Plutus by updating the UPLC specification for the built-in value type and related functions, and by improving the metatheory and certification infrastructure used to reason about compiler transformations. These changes make the formal-assurance workflow easier to maintain, debug, and scale to larger programs.

Key Pull Requests Merged​

• Specification of the built-in value type and functions
• Rename UPLC scope variable in the metatheory
• Mutually recursive PIR function inlining
• Lightweight benchmarking in the uplc executable
• Fuse unionWith and checkBinRel in PlutusLedgerApi.V1.Data.Value
• Certifier: Generate one Proof .agda file per certified pass
• Optimal non-builtin valueOf in plutus-ledger-api Data.Value
• Metatheory: define semantic versions of value and purity
• Certifier: deduplicate ASTs in agda certificate
• Fix the FloatDelay compiler optimization pass

High level overview​

This week, the Mithril team completed the wiring of the recursive SNARK proof in the aggregate signature, and its integration in the end-to-end tests and its deployment in a test network. They continued work on refactoring the unsafe SNARK setup and refactoring the preparation of the prover input for the recursive SNARK aggregation primitives.

The team also completed the implementation of the monitoring for Cardano blocks and transactions in the protocol dashboard, the integration tests for the unknown signed entity type in the signer and aggregator, and the enhancements of the aggregator state machine to support the Blocked state. They continued work on the release of the 2626 distribution, the upgrade to Cardano 11.1, and the update of the DMQ node to 0.7.0.0.

Finally, the team fixed some flakiness in the Hydra CI, enhanced the versions bump script and implemented a GitHub workflow to automate the marking of stale issues and pull requests.

Low level overview​

Features​

• Completed the issue Recursive SNARK aggregation primitives: Wire SNARK proof in aggregate signature #3141
• Completed the issue Implement recursive SNARK proof generation and verification in end-to-end tests #3142
• Worked on the issue Refactor unsafe SNARK setup #3300
• Worked on the issue Recursive SNARK aggregation primitives: Refactor preparation of prover input #3319

Protocol maintenance​

• Completed the issue Implement monitoring for Cardano Blocks and Transactions in Protocol dashboard #3157
• Completed the issue Activate CardanoBlocksTransactions in Mithril networks #3160
• Completed the issue Add integration tests for unknown signed entity type in signer and aggregator #3296
• Completed the issue Flaky CI on hydra run of ci/hydra-build:x86_64-linux.mithril-common #3329
• Completed the issue Enhance versions bump script #3334
• Completed the issue Mark stale issues and PRs with GitHub workflow #3339
• Completed the issue Certification stopped on ivc-snark-preview network #3351
• Worked on the issue Ship Mithril signer node binary in Cardano node bundle in GitHub #3011
• Worked on the issue Release 2626 distribution #3271
• Worked on the issue Enhance aggregator state machine to support Blocked state #3333
• Worked on the issue How to reduce the IVC tests duration #3343
• Worked on the issue Upgrade to Cardano 11.1 #3346
• Worked on the issue Update DMQ node to 0.7.0.0 #3358

High level summary​

• Leios prototype development (Treasury Funding Initiative 4: Ouroboros Leios Implementation):
  • Chain selection and the volatile database now handle ranking blocks and Endorser Blocks that arrive out of order. A certifying ranking block that arrives before the Endorser Block it certifies is stored but held back from chain selection until the Endorser Block shows up. A new header bit also lets a syncing node fetch Endorser Blocks that were certified on the historical chain (#2076).
  • Fixed a bug where the LeiosFetch budget leaked when a peer disconnected. Requests in flight at the time of the disconnect were never cleared, so their share of the budget was never returned, and a node could eventually stop fetching altogether. This is a plausible cause of the forks seen recently on the testnet (#2083).
  • Corrected Endorser Block application to take the slot from the provided ledger state (#2085).
  • Voting and certification now happen over the announcing ranking block hash (#2086).
  • The db-synthesizer config parser now honors ExperimentalHardForksEnabled, so experimental hard forks can be enabled when generating synthetic chains (#2077).
  • Made the proto-devnet demo start up more reliably by holding back the transaction generator until the nodes are ready, and reduced the tip-observation frequency for the secondary nodes (ouroboros-leios#942, ouroboros-leios#943).
• LSM-trees and UTxO-HD (Treasury Funding Initiative 10: LSM including UTXO-HD):
  • Reworked the snapshot-converter into a command tree. It now offers a daemon mode that watches a node's snapshot directory and converts each exported LSM snapshot into the portable in-memory format as it is produced, a one-shot conversion in either direction, and commands to move snapshots in and out of an offline LSM database. This supports the Mithril workflow, where signers need snapshots in a single agreed format (#2064).
• Documentation (Treasury Funding Initiative 17: Maintenance and Support):
  • Added configuration documentation to the consensus website (#2065).
  • Minor improvements to the Genesis documentation (#1916).