---
week: 2026-W39
weekStart: '2026-09-21'
weekEnd: '2026-09-27'
generatedAt: '2026-09-28'
counters:
  prsMerged: 5
  prsOpened: 7
  issuesClosed: 0
  issuesOpened: 0
  releases: 0
  reposTouched: 2
  commits: 47
  comments: 1
activity:
  - deliverable: reactive
    items:
      - type: pr
        title: Fix bug with cluster-tests getting transactions rejected due to stalled processing
        url: https://github.com/cardano-scaling/hydra/pull/2889
        repo: cardano-scaling/hydra
        author: noonio
      - type: pr
        title: Delegated demo example
        url: https://github.com/cardano-scaling/hydra/pull/2888
        repo: cardano-scaling/hydra
        author: noonio
      - type: pr
        title: Changelog clarity
        url: https://github.com/cardano-scaling/hydra/pull/2887
        repo: cardano-scaling/hydra
        author: noonio
      - type: pr
        title: bump cardano-node; and fix a blockfrost nightly
        url: https://github.com/cardano-scaling/hydra/pull/2877
        repo: cardano-scaling/hydra
        author: noonio
      - type: pr
        title: Move some tests away from hydra-cluster
        url: https://github.com/cardano-scaling/hydra/pull/2875
        repo: cardano-scaling/hydra
        author: noonio
      - type: pr-opened
        title: Check an acknowledgement's signature before recording it
        url: https://github.com/cardano-scaling/hydra/pull/2884
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Model a party that deviates and judge what the head signed
        url: https://github.com/cardano-scaling/hydra/pull/2883
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Require a refusal of a snapshot request to be unanimous
        url: https://github.com/cardano-scaling/hydra/pull/2882
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Hold re-posts back while catching up, and keep a removed event decodable
        url: https://github.com/cardano-scaling/hydra/pull/2881
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Re-post erased settlements on ticks only, and bound the unretained notes
        url: https://github.com/cardano-scaling/hydra/pull/2880
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Derive the rollback horizon from the network
        url: https://github.com/cardano-scaling/hydra/pull/2879
        repo: cardano-scaling/hydra
        author: v0d1ch
      - type: pr-opened
        title: Retain every settled increment and decrement for rollback replay
        url: https://github.com/cardano-scaling/hydra/pull/2878
        repo: cardano-scaling/hydra
        author: v0d1ch
    commitCounts:
      cardano-scaling/hydra: 44
  - deliverable: M6
    items: []
    commitCounts:
      cardano-scaling/hydra-updates: 3
---

## Highlights

5 PRs merged, 7 opened and 47 commits across two repos, with no releases
and no issue activity. One merge is last week's test migration; the other
four are a cardano-node bump, a fix to how the node decides its network is
backed up, a new delegated-head demo, and a changelog tidy. The seven PRs
opened this week were all closed unmerged before the week ended.

**Reactive.** The test migration described last week (#2875) merged Monday.

cardano-node moved from 11.0.1 to 11.1.2 (#2877, merged Wednesday, closes
#2876), on the suspicion that the old version was behind a nightly failure.
The demo docker-compose image, still on 10.6.2, came along too. The same PR
fixed a Blockfrost timing test that failed nightly and a flaky "reports a
stalled broadcast" test, which now scrapes metrics with retries.

The node's network outbox reported `BacklogFull` at a fixed 1000 pending
messages, so under constant load a node refused `NewTx` while its network
was still draining normally. In the end-to-end benchmarks each refused
transaction then invalidated every later one in its client's chain ("All
inputs are spent"), which is why the sustained-load and plateau scenarios
had been failing on master. The outbox now also judges the backlog by how
long it would take to drain at the recent completion rate, and reports
`BacklogFull` only once that exceeds `noProgressFor`; the 1000 cap stays as
a memory backstop (#2889, merged Friday).

A new delegated-head demo (#2888, merged Friday) runs a head whose
operators commit no funds of their own: two independent addresses
increment funds into it, transact, and leave by decrement. One of them
builds its deposit transaction in JS and submits it straight to L1, to show
the hydra-node API isn't required for depositing. It runs with
`nix run .#delegated-demo`. The changelog was also tidied (#2887, Thursday).

Seven stacked PRs on rollback handling (#2878 to #2884) were opened Tuesday
and closed Thursday and Friday without merging.

**KPI & Outcome Achievement (M6).** Routine only: the W38 note published.