This week’s news is brief but big. Holochain v0.0.50 has been released and included in the latest blessed version of Holonix, the Holochain developer tools distribution. It comes with fixes for a long list of consistency and performance issues.

HoloFuel testing has moved on from Core Community testing to Pre-Release testing. This staged rollout lets us catch any remaining issues before we release to all HoloPort owners.

We also want to remind you of Holochain DevCamp 7, which starts next Tuesday. Apply now!


  • Holochain v0.0.50-alpha4 released and blessed
  • HoloFuel enters Pre-Release testing
  • Community Mutual Credit hApp benefits from Holochain fixes
  • Register for DevCamp 7

Holochain v0.0.50-alpha4 released and blessed

This newest release of the Holochain conductor and dev tools fixes a lot of longstanding and new performance and consistency issues seen over the last few releases. These were fixed in our push to get HoloFuel onto HoloPorts for alpha testing – if there ever were an app to poke at the weak spots in Holochain’s codebase, HoloFuel is it. I’m super grateful to Eric H-B and David B for working so hard to fix the bugs and get this into your hands.

The fixes are too numerous to mention here, but the general categories are:

  • Lower latency between UI and conductor, including the ability to run multiple zome calls in parallel
  • Faster DHT data propagation times
  • Less CPU, memory, and network consumption
  • Faster and correct validation, particularly when the author is offline
  • No discrepancies between what nodes are holding and what the sim2h switchboard server thinks they’re holding (this solves problems with unavailable entries and metadata)

We’ll likely cut a few more small releases to fix any issues that we uncover while testing HoloFuel with ever greater numbers of users. After that, we intend to start rolling out more extensive changes to Holochain to improve performance, correctness, and maintainability.

Upgrade now!

Because of the large number of fixes, we encourage all developers to upgrade to this version. If you’re already using the easy install procedure, you don’t need to do anything special—just enter your nix-shell as usual and start hacking. I recommend that you update your HDK dependency versions (`hdk`, `holochain_wasm_utils`, and optionally `hdk_proc_macros`) in all of your zomes’ `Cargo.toml` files. And if you’re using the holochain-anchors crate in your projects, you can make sure you’re using the version that targets the right HDK with this line:

holochain-anchors = { git = "", tag = "v0.2.6" }

HoloFuel enters pre-release testing

In the last Dev Pulse we announced that HoloFuel was finally released to Core Community testers, a small group of HoloPort owners dedicated to rigorously testing updates and reporting their experiences. This process went quite well, so we’ve rolled it out to Pre-Release testers. You can read the full story, along with our rollout plans, in this week’s Leadership & Org Update. The tl;dr is that HoloFuel (with Test Fuel) has pushed Holochain to make big improvements to reliability and performance, as shared above, and that means that the initial version of HoloFuel is almost ready for general release.

Community Mutual Credit hApp benefits from Holochain fixes

Because we’re talking about currencies so much lately, I’d like to draw attention to another hApp that is now working thanks to the fixes in Holochain. Guillem Córdoba’s Community Mutual Credit hApp, a project designed to showcase patterns for building a particular sort of currency with Holochain. This currency features a private space for transactions, and a public ‘lobby’ space that allows new member hopefuls to ask existing members to ‘vouch’ for them in the private space and thus permit them to join.

This hApp was blocked by the same Holochain issues that were causing problems in HoloFuel testing. Previously Holochain had troubles propagating links, so member handles were disappearing from the lobby and vouches were disappearing from the private space. Now that this is fixed, it’d be great to test the application again. Join the forum, find a buddy, and let’s get transacting!

Register for DevCamp 7

The first session of the next community-led DevCamp is next Tuesday at 13:30 UTC. We’re excited by the response so far—184 people have registered! We invite you to join this course and dig deep into the core concepts, the framework and HDK, and the principles of good hApp design. Each week there’ll be two live sessions (recorded if you can’t make the time) along with follow-up activities, forum conversations, and peer code review.

The cost is free, the materials are great, the dev community is growing, and the facilitators are friendly and knowledgeable. Sign up now at !

Development status


  • Holochain Core: 0.0.50-alpha4 (blessed) | Changelog
  • Holonix: 0.0.80 (blessed) | Changelog
  • Tryorama: 0.3.4 (blessed)
  • hc-happ-scaffold: 0.1.0 (blessed) | Project
  • Holoscape: 0.0.9-alpha (contains Holochain Core 0.0.47-alpha1) | Download

Blessed (available via

  • Holonix: 0.0.80
  • Holochain Core: 0.0.50-alpha4
  • hc-happ-scaffold: 0.1.0