High level summary​

Leios continued to be the main focus this cycle and moved well beyond prototype on several fronts. Dijkstra forecasting for Leios landed, the forecasting itself was simplified by keeping stake data only in snapshots, and DijkstraEraForecast was extended with the Peras protocol parameters. We defined Leios' EndorserBlock, added a ledger state query for the Leios committee, switched the Leios header KES signature verification to use MemoBytes, and fixed pool BLS key handling so the key's epoch number is only renewed when the key is actually new. These were backed by tests for the Leios committee and stake distribution when injecting genesis data, and by integration of the latest Leios changes for week 41.

PlutusV4 reached a milestone for the Dijkstra era: eraMaxLanguage is now set to PlutusV4, and AlonzoTxWits encodes and decodes PlutusV4 scripts starting with Dijkstra. Work on sub-transactions continued, with allInputsTxBodyF now looking into sub-transactions, top-level supplemental datums allowed for sub-transactions, and tests added for refunds in the consumed value across a batch. On the Dijkstra era more broadly, we fixed VRF reuse at the epoch boundary, started tracking the VRF key hashes of genesis stake pools, moved NonMyopicMemberRewards into the ledger, added missing getters to AnyEraTxBody, and renamed requiredTopLevelGuardsL while bringing in its outstanding tests.

On testing and releasing we added further Entities tests, treasury value and reference-script size tests, enabled bootstrap addresses in conformance, updated the formal ledger specification, and bumped the Plinth version in the Plutus preprocessor modules. Infrastructure changes included a cardano-data changelog fix for the pointWise to pointwise rename, a round of package version bumps across the changelogs following a CHaP release, and the usual dependency bump.

Low level summary​

Features​

• PR-6124 - Make AlonzoTxWits decode and encode PlutusV4 scripts starting with Dijkstra
• PR-6129 - Switch allInputsTxBodyF to look into sub-transactions
• PR-6130 - Move NonMyopicMemberRewards to Ledger
• PR-6140 - Add missing getters to AnyEraTxBody
• PR-6120 - Use MemoBytes for Leios header KES signature verification
• PR-6134 - Simplify forecasting by keeping stake data only in snapshots
• PR-6137 - Allow TopTx SupplementalDatums for SubTx
• PR-6148 - Add Dijkstra forecasting for Leios
• PR-6092 - Fix VRF reuse at epoch boundary in Dijkstra
• PR-6133 - Track the VRF key hashes of genesis stake pools in Dijkstra
• PR-6136 - Rename requiredTopLevelGuardsL and add tests from #6020
• PR-6126 - Extend DijkstraEraForecast with Peras protocol parameters
• PR-6168 - Add ledger state query for Leios committee
• PR-6170 - Renew pool BLS key epoch number only when the key is new
• PR-6174 - Define Leios' EndorserBlock

Testing​

• PR-6125 - Tests for refunds in the consumed value across a batch
• PR-6109 - Set Dijkstra's eraMaxLanguage to PlutusV4, fix tests
• PR-6141 - Bump Plinth version in plutus preprocessor modules
• PR-6132 - Additional Entities tests
• PR-6156 - TreasuryValue and RefScriptSize tests
• PR-6167 - Add tests for verifying Leios committee and stake distribution when injecting genesis data
• PR-6149 - Update formal ledger specification
• PR-6182 - Enable boostrap addresses in conformance

Infrastructure and releasing​

• PR-6131 - Fix cardano-data CHANGELOG with Data.CanonicalMaps.pointWise rename to pointwise
• PR-6135 - Bump package version in all CHANGELOG.md files following release in CHaP
• PR-6143 - Bump urllib3 from 2.7.0 to 2.8.0 in /doc
• PR-6166 - Leios: integrate latest changes for 2026w41

High level overview​

This week, the Mithril team completed hardening the SNARK primitives and distinguishing the canonical bytes encoding in the STM library. They kept working on resolving the SNARK verification key collisions deterministically in the key registration, publishing the immutable archives directory under an IPNS name in the aggregator, and identifying a crate for the user interaction of the setup command.

The team completed the upgrade to Cardano node 11.1.3, adding a keypair generation tool in the aggregator CLI, and detecting the yanked crates in the CI. They also worked on the new distribution release, the upgrade to Cardano node 11.2, the update of the DMQ node to 0.7.2.0, and kept investigating the blocks and transactions verification failure on the testing-preview network.

Finally, they fixed the WASM client tests which terminated themselves, the firewall configuration in the infrastructure which opened unused Mithril relay ports when the real DMQ node is used, and the DMQ node SRV record prefix in the signer documentation.

Low level overview​

Features​

• Completed the issue SNARK primitives hardening #3557
• Completed the issue Distinguish canonical bytes encoding in the STM library #3572
• Worked on the issue Resolve SNARK verification key collisions deterministically in the key registration #3591
• Worked on the issue Publish the immutable archives directory under an IPNS name in the aggregator #3606
• Worked on the issue Identify a crate to use for the user interaction (TUI) of the setup command #3618

Protocol maintenance​

• Completed the issue Upgrade to Cardano 11.1.3 #3601
• Completed the issue Add generate keypair tool in aggregator CLI #3584
• Completed the issue Detect yanked crates in the CI #3589
• Completed the issue Fix make -C mithril-client-wasm test which terminates itself #3590
• Completed the issue Firewall opens unused Mithril relay ports when the real DMQ node is used #3611
• Completed the issue Fix DMQ node SRV record prefix in the signer documentation #3620
• Worked on the issue Release 2642 distribution #3498
• Worked on the issue Upgrade to Cardano 11.2 #3585
• Worked on the issue Update DMQ node to 0.7.2.0 #3602
• Worked on the issue Blocks and transaction verification fails on testing-preview #3526

High level overview​

This week, the Mithril team completed adding a Proof of Bound Possession for the SNARK verification keys, renaming the future_snark feature to snark, adding the missing conversion and error-path tests in IVC SNARK, and testing the SNARK infrastructure to full security parameters with the Midnight fix. They kept working on hardening the SNARK primitives.

The team completed adding an IndexedDB backend for the certificate chain cache in the WASM client and documenting the certificate chain cache, fixed the IPFS end to end tests failing when dist.ipfs.tech is unreachable, and fixed the crates publication dry run failing in the nightly. They also worked on the new distribution release, the upgrades to Cardano node 11.1.3 and 11.2, the update of the DMQ node to 0.7.2.0, a keypair generation tool in the aggregator CLI, and kept investigating the blocks and transactions verification failure on the testing-preview network.

Finally, they completed the upgrade to Rust 1.99, and fixed the missing SPO aliases in the explorer, the flakiness of the end to end tests caused by the devnet scripts, and the cloud uploader cache which only held the first 1000 files.

Low level overview​

Features​

• Completed the issue Add a SNARK verification key Proof of Bound Possession #3537
• Completed the issue Rename future_snark feature to snark #2814
• Completed the issue Add the missing conversion and error-path tests in ivc_halo2_snark #3470
• Completed the issue Test SNARK infrastructure to full security parameters with the Midnight fix #3593
• Completed the issue Add an IndexedDB backend for the certificate chain cache in the WASM client #3524
• Completed the issue Document the certificate chain cache #3525
• Worked on the issue SNARK primitives hardening #3557

Protocol maintenance​

• Completed the issue Upgrade Rust to version 1.99 #3578
• Completed the issue IPFS e2e tests fail when dist.ipfs.tech is unreachable #3582
• Completed the issue Crates publication dry run fails in the nightly since mithril-common 0.8.0 #3581
• Completed the issue Some SPO aliases are missing in the explorer #3518
• Completed the issue Fix flakiness of the end to end tests in the CI caused by the devnet scripts #3596
• Completed the issue Fix the cloud uploader cache which only holds the first 1000 files #3594
• Worked on the issue Release 26XX distribution #3498
• Worked on the issue Upgrade to Cardano 11.1.3 #3601
• Worked on the issue Upgrade to Cardano 11.2 #3585
• Worked on the issue Update DMQ node to 0.7.2.0 #3602
• Worked on the issue Add generate keypair tool in aggregator CLI #3584
• Worked on the issue Fix make -C mithril-client-wasm test which terminates itself #3590
• Worked on the issue Blocks and transaction verification fails on testing-preview #3526

High level summary​

The Plutus team has published release 1.71.0.0, which includes the full Plutus V4 script context and will be integrated into node release 11.2. The release also adds Plutus Core language version 1.2.0 and the cost models for keepPolicies and dropPolicies (CIP-0168).

We've opened CIP-0205, which proposes to remove scope checking for Plutus scripts. As usual, we encourage everyone to read it and leave comments - we would like as much feedback as possible.

Other than these, casing on built-in types is now specified in the Plutus Core specification, and the guardrail script has been made smaller and cheaper by using BuiltinList and BuiltinPair. Work in progress includes making the uplc and plc executables easier to obtain (publishing them to CHaP, and shipping prebuilt macOS binaries built by Hydra), and bringing the specification further up-to-date.

Key Pull Requests Merged​

• Add Plutus Core version 1.2.0
• Cost models for keepPolicies and dropPolicies (CIP-0168)
• Add semvar F and G for Dijkstra
• Specify casing on built-in types
• Change ttisScriptPurposes to ttisRedeemerHashes
• Add property tests for V4 script context helpers
• Fix scope check
• Guardrail: improve cost/size using BuiltinList/BuiltinPair
• Fix plugin unable to resolve variable reference when parsing list

Pull Requests In Progress​

• Publish plutus-executables to CHaP
• Ship prebuilt executables for macOS, built by Hydra
• Apply script deserialisation bounds unconditionally
• Add plugin option to dump compilation timing

High level summary​

• Leios prototype development (Treasury Funding Initiative 4: Ouroboros Leios Implementation):
  • Moved the Leios database (LeiosDB) from the leios-prototype branch to main. The SQLite backend, which was one large module, is now split into modules by job: schema, queries, inserts, reads, the write queue, and maintenance (#2311).
  • The mempool now reserves room for an Endorser Block, in addition to the room for a ranking block. Each transaction gets a second measure, its cost in an Endorser Block, which includes its entry in the Endorser Block (a 32-byte hash and the transaction size). In the Dijkstra era, the Endorser Block capacity comes from the protocol parameters. In every earlier era it is zero, so the mempool capacity of those eras does not change (#2312, #2325).
  • A mempool snapshot can now split its transactions into two parts: the longest prefix that fits a ranking block, and the next run that fits an Endorser Block. The forge still passes a zero Endorser Block capacity, so it selects the same transactions as before (#2320).
  • Added the trace TraceMempoolCapacityChanged. The mempool capacity comes from the protocol parameters, so a parameter update or an era transition changes it, and no trace reported this before. With the Endorser Block term, one such change can be several megabytes (#2304).
  • Two performance fixes in the prototype. A mempool read no longer waits while a writer holds the mempool state (#2308). Block application now reads the LeiosDB through a read-only connection, so it does not compete with the writer thread for the database (#2315).
  • Fixed a crash in the database tools. A LeiosDB handle links its background copier thread to the thread that opened it. No tool closed its handle, so the runtime raised an exception in the copier, and the link passed it on to the tool. Every tool now closes its handle. The same change fixes three shutdown defects that closing exposed, for example a close that blocked forever (#2314).
  • The Leios CBOR decoders now reject malformed input from a peer. A hash must be exactly 32 bytes, and the decoder checks each count that a peer declares against maxTxsPerEb before it allocates memory. This closes findings LEI-004, LEI-005 and LEI-009 from the Anastasia Labs audit (#2358, for ouroboros-leios#1125).
  • To stress test the Leios testnet, LeiosNotify now sends up to 1000 requests before it waits for a reply (#2366).
  • Released the prototype versions prototype-2026w39 and prototype-2026w40a (ouroboros-leios#1117, ouroboros-leios#1131, with the node integration in cardano-node#6708 and cardano-node#6722). The first release has the mempool, database and shutdown fixes above. It also shrinks the SQLite write-ahead log back to 64 MiB after a burst of writes, for example a testnet sync (ouroboros-consensus#2332). The second release keeps votes for the 128 most recent points only, so the vote state no longer grows without limit. This bound lets us take load readings, but it does not resist an adversary (ouroboros-consensus#2367).
• Maintenance and support (Treasury Funding Initiative 17: Maintenance and Support):
  • Released ouroboros-consensus 5.0 (#2356, with the dependency updates in #2341 and #2352). The release has the reworked Peras API and drops node-to-client versions below v23. The default ledger snapshot policy now takes a snapshot every 40 * k slots, where k is the security parameter, which is one snapshot a day on mainnet. A background thread now writes the snapshots. The mempool now moves a transaction from an older era to the current era in one step: it encodes the transaction in its own era and decodes it in the current era. Before, it translated the transaction through every era in between.
  • Released ouroboros-consensus 5.1.0.0 (#2368, ported to main in #2369). At startup, the node now traces its ledger snapshot policy. The snapshot interval is in slots, but the write delay and the rate limit are in seconds. So settings that suit mainnet, where a slot is one second, can be wrong on a testnet with shorter slots. If the delay or the rate limit is as long as the interval or longer, the node emits the warning ImplausibleSnapshotPolicy.
  • Moved the tracing instances for consensus types from cardano-node into the new ouroboros-consensus:tracing sublibrary. A change to a traced type and the change to its log output can now go in one commit. Some log output changes: a mempool trace at the detailed level logs a transaction as hex CBOR instead of a Haskell Show rendering, and a rejected transaction always logs the reason (#2244).
  • The database tools now read the node configuration with cardano-config, and db-synthesizer reads its forging keys with cardano-keys. The tools now apply the same rules as cardano-node. Before, db-synthesizer could forge blocks in an era that a node with the same configuration file would not enter. One visible change: every genesis file in the configuration must now come with its hash (#2259, #2335).