Week 41 · 2026

Highlights

5 PRs merged, 1 other opened and 63 commits across two repos, with no releases. Two issues were opened: the Aiken bump (#2893), closed by its merge, and a migration away from the deprecated cardano-api transaction body API (#2896), left open. The merges raise the snapshot transaction cap, correct some benchmark measurements, tighten deposit observation and decommit handling, and update the Aiken toolchain. The one other PR, a cardano-node and cardano-api bump, was still in review at the week's end.

Reactive. The snapshot cap rose from 1000 to 4000 transactions (#2856, merged Tuesday, open since 4 September). Each snapshot round does work over the pending backlog, so a small cap makes a heavily loaded head repeat that work more often. In the recorded local three-node benchmark, draining 24000 self-transfers took 13.50 seconds at the new cap against 37.04 at the old one: effective throughput rose from 648 to 1778 tx/s, and median confirmation time fell from 29.1 to 12.3 seconds. These are burst-drain measurements with minimal transactions and loopback etcd; the cap does not bind under light load. Larger caps still helped in the sweep, but gains tapered while request size grew, so 4000 leaves ample room below etcd's request limit. The cap limits what a leader proposes; followers already accept larger requests, and the separate limit on the head's UTxO size is unchanged.

The PR benchmark reports were tightened Friday (#2898). The sustained-TPS slope now needs eight snapshot points inside its measurement window, up from four, so a run with only a handful of large snapshots no longer gets a misleading slope. A comparison row is coloured only when at least three quarters of its pairs measured the metric, as well as meeting the existing noise and direction checks. The memory row now reports mean live heap over major garbage collections during transaction processing, taking the largest node's mean, instead of a lifetime peak that small scenarios could set during startup. The metric is omitted if no node had a major collection in that window; monitoring and benchmark tests and documentation were updated alongside it.

Two protocol follow-ups also merged Friday (#2899). A fanout whose first output looked like a deposit, and whose transaction had an upper validity bound, could be observed as a deposit instead: the deposit observer matched the output's shape before the fanout observer ran, leaving the nodes closed even though the fanout had landed. Head transactions are now checked first, and any transaction spending a head output is excluded from deposit observation. Regression coverage includes full and final partial fanouts.

The same PR tightened the pending-decommit case from last week's #2891. A snapshot request at the same version must keep the decommit the confirmed snapshot is still settling. Dropping it, or substituting a deposit, could leave the honest nodes without a snapshot they could use to close and fan out once the decrement landed. Such requests are now rejected with ReqSnDecommitNotSettled. Side-loading a snapshot also keeps the matching decommit if it is still settling, instead of pruning it with the unconfirmed transactions. The protocol documentation, Agda reference and tests were updated to match.

Aiken moved from 1.1.9 to 1.1.24 and its standard library from 2.1.0 to 4.0.0 (#2894, merged Tuesday, closes #2893). The validator utility was adapted to the library's Assets type, the compiled blueprint regenerated, and the cached standard library used by the Nix tests updated. A separate tidy that day (#2895) removed Nix deprecation warnings from just check by replacing uses of system with stdenv.hostPlatform.system.

The next dependency upgrade, to cardano-node 11.1.3 and cardano-api 11.7, opened Thursday (#2897). Migrating the deprecated transaction body API to Cardano.Api.Experimental is tracked separately in #2896, keeping that larger redesign out of the version bump.

KPI & Outcome Achievement (M6). The W40 note published, the tracker recorded the workshop's completion of Ecosystem Support, and the delivery timeline was tidied. Shipped dates now have their own markers and tooltips, distinct from the deadlines they met.