> For the complete documentation index, see [llms.txt](https://cardanoupgrades.docs.intersectmbo.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cardanoupgrades.docs.intersectmbo.org/general/hard-fork-working-group-meeting-minutes/28th-may-2026.md).

# 28th May 2026

#### Agenda

1. [Action items from the last call](https://cardanoupgrades.docs.intersectmbo.org/van-rossem-upgrade/hard-fork-working-group-meeting-minutes/26th-may-2026#action-items-and-next-steps) - Bosko
2. [Node 11.0.1](https://github.com/IntersectMBO/cardano-node/releases/tag/11.0.1) & [DBSync 13.7.1.0](https://github.com/IntersectMBO/cardano-db-sync/releases/tag/13.7.1.0) - Sam/Ramsay/Jeff
3. [Van Rossem Upgrade Update](https://docs.google.com/presentation/d/1pEFh_GC3Nx2nTVPXj9bke9R7C9Bkr8Hk/edit?slide=id.p1\&pli=1#slide=id.p1) - Bosko, all
   1. Ogmios [PR](https://github.com/CardanoSolutions/ogmios/pull/461)
      1. van Rossem only support vs van Rossem & Dijkstra support
   2. Kupo [PR #1](https://github.com/CardanoSolutions/kupo/pull/203) & [PR#2](https://github.com/CardanoSolutions/kupo/pull/204)
   3. [Readiness tracker](https://docs.google.com/spreadsheets/d/1ECoYFCtrRtFX3BvqfhaZi6FxlXQMoTGP/edit?usp=sharing\&ouid=106134819668558877362\&rtpof=true\&sd=true)
4. van Rossem hard fork progress - Bosko
   1. PreProd
      1. [Cardanoscan](https://preprod.cardanoscan.io/govAction/gov_action108a5htqnmlp89ffn2ucf7u9u33s0r9gpx7eytpdc2q28y50ly42qqf9jcen)
      2. [Cexplorer](https://preprod.cexplorer.io/gov/action/79fb4bac13dfc272a53357309f70bc8c60f1950137b24585b850147251ff2554%25230)
      3. Are we ready to vote, ratify and enact hf ga on preprod? (first next possible enactment date is **5th June** if its voted for until **31st May** - next epoch boundary on PreProd)
   2. Mainnet
      1. Mainnet hard fork initiation governance action submission date - 29th May, 3rd June, 8th June, 13th June, 18th June
5. Plutus Cost Model - Kevin, Ryan, Bosko
   1. Mainnet - submitted on 26th May
6. van Rossem comms - Ian / Larisa
   1. Comms plan - CF, Midnight, Shielded, Emurgo, Intersect, IO
      1. Weekly comms meeting
   2. Comms in the last week - anything we missed
   3. Comms in the week ahead
7. [Risk log](https://docs.google.com/spreadsheets/d/1DSAiayrPOhhzSKKKljbd2WxHQPFmzKsvoyyA-BJUDg8/edit?gid=1105903724#gid=1105903724)
8. AOB

#### Key materials

* Summary
  * Latest version of DBSync is [13.7.1.0](https://github.com/IntersectMBO/cardano-db-sync/releases/tag/13.7.1.0) and its recommended to upgrade to that version
    * If you are running DBSync version 13.7.0.5, it is also van Rossem compatible, and it just needs migration script executed as described in the release notes
  * Ogmios is forked, will be made van Rossem compatible shortly through the respective transparent PR, and it will give much needed time to Ogmios author to assess changes from his perspective and merge the into the original code for the mainnet fork enactment moment
    * Respective PR wont change any of the frontend, its meant to provide the service that communicates with the node
    * It is reasonable to reintegrate and retest once the Ogmios van Rossem compatible changes are merged in the original repo
  * Kupo is close to be done and ready, possibly even today
  * Based on the above Hard Fork Working Group recommends without any voiced or written objections:
    * Forking the PreProd wtih ratification happening on the next epoch boundary on 31st May and enactment an epoch later, on 5th June
    * Go/No go decision meeting for the submission of the hard fork initiation governance action to be held on 8th June
      * Should Hard Fork Working Group decide on 8th June that its a "go", hard fork initiation governance action will be submitted on the same day, 8th June
  * Plutus Cost Model parameter update governance action, submitted on 26th May, is already gaining positive traction 15.59% off yes votes
    * mincommitteesize parameter update governance action, chained to the plutus cost model one, is expected to be submitted on mainnet early next week
  * Readiness tracker is updated with more tools, libraries, indexers, SPOs becoming ready
  * Risk log was assessed and adjusted accordingly in the light of the discussion on todays call and is showing that the effective risk management strategies are already yielding results
* Hard Fork Working Group communication channels
  * [Discord](https://discord.com/channels/1136727663583698984/1242097284619960411) — `#wg-hard-fork`
  * [Weekly bulletins](https://x.com/IntersectMBO)
  * [Luma calendar](https://luma.com/calendar/cal-TMjYNpSY4huYYif)
* [van Rossem Upgrade Update](https://docs.google.com/presentation/d/1pEFh_GC3Nx2nTVPXj9bke9R7C9Bkr8Hk/edit?slide=id.p1\&pli=1#slide=id.p1)
* [van Rossem readiness tracker](https://docs.google.com/spreadsheets/d/1ECoYFCtrRtFX3BvqfhaZi6FxlXQMoTGP/edit?usp=sharing\&ouid=106134819668558877362\&rtpof=true\&sd=true)

#### **Action items and next steps**

* **Sam/John/Jeff:** Provide respective Ogmios and Kupo PRs as soon as they are ready this week
* **John:** Make sure that the live hard fork initiation governance action on PreProd has sufficient votes to be ratified on the next epoch boundary on 31st May and subsequently enacted on 5th June
* **Ian (and the rest of the wide comms team):** To update the comms plan witht the following:
  * Communicate hard fork working group decision for PreProd forking
  * Communicate the approach on Ogmios readiness (forking original repo) with an emphasis on the fact that once Ogmios author review the changes they are expected to become part of the original repo too.
    * It is worth mentioning that there would be no frontend changes and that the respective PR is meant to provide the service that communicates with the node
  * Comms piece needs to also point out that it would be reasonable to expect that reintegration and retesting are done after the van Rossem compatible codes ends up being merged in the original Ogmios repo
  * Communicate Kupo readiness upon confirmation from the hard fork working group
* **Bosko:** Schedule the Go/No go call for the decision on submission of van Rossem hard fork initiation governance action on mainnet for 8th June
* **Bosko:** [The readiness tracker](https://docs.google.com/spreadsheets/d/1ECoYFCtrRtFX3BvqfhaZi6FxlXQMoTGP/edit?usp=sharing\&ouid=106134819668558877362\&rtpof=true\&sd=true) should be updated with the certain thresholds for nodes running latest stable version 11.0.1 (50%), top 20 dapps, top 20 exchanges by liquidity, etc. That would also bring additional confidence layer for a decision to submit hard fork initiation governance action on mainnet


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