I’ll add a bit more detail to what Zooko shared.
First off, thanks for the question. I can’t speak for the other teams, but I can share how we’re thinking about it at Shielded Labs. There are two major efforts happening in parallel, and it’s helpful to separate them because they’re often discussed together. The first is the Ironwood (NU6.3) upgrade. The second is the migration from zcashd to the new Z3 stack built around Zebra, Zaino, and Zallet. The current goal is to complete both efforts by late July.
With regard to Ironwood, the teams at Project Tachyon, Valar Group, ZODL, the Zcash Foundation, and Shielded Labs have been working hard and have made significant progress over the past several weeks. Development is moving forward on schedule, and testnet activation of the new consensus rules is expected shortly. Work is also continuing on formal verification of the new circuit, with the goal of completing a proof of soundness before Ironwood activates.
Development of Z3 is also making progress. The challenge is that key pieces of the new stack, specifically Zallet and Zaino, are still under development and aren’t yet ready for production use, which leaves mining pools, exchanges, and other infrastructure partners with limited time to deploy and test everything before Ironwood activates.
ZODL and the Zcash Foundation have been leading outreach efforts to help mining pools and exchanges prepare for the migration. At Shielded Labs, we’ve also been speaking directly with partners to understand how we can best support the transition.
The consistent feedback we’ve received is that completing both the Ironwood upgrade and the migration to Z3 on the current timeline will be challenging. That seems consistent with a questionnaire Pacu recently circulated, where most did not respond and those who did provided mixed responses, with some indicating they’ll be ready while others said they need additional time.
From Shielded Labs’ perspective, our primary concern is security. We’d prefer to see the Ironwood implementation and the components of the Z3 stack undergo independent third-party security audits once development is complete, before recommending that infrastructure providers deploy them in production.
For that reason, we believe it’s worth considering a few options that could reduce deployment risk:
- Delay Ironwood activation to give infrastructure partners more time to complete the transition to the Z3 stack.
- Use the additional time to complete independent third-party security audits of the production software before deployment.
- Alternatively, decouple the Ironwood upgrade from the Z3 migration by providing temporary Ironwood-compatible
zcashdsupport. As I mentioned on the most recent Arborist call, Shielded Labs is currently working on providing this option for partners who need additional time. - We’ve also asked @earthrise to conduct a risk assessment of the strategy of requiring the ecosystem to migrate from
zcashdto the new Zebra-based stack on the current timeline. We plan to share a version with the core developers this week and may also publish a version for the community.
Ultimately, we all share the same goal to activate Ironwood as quickly as possible while making sure our partners can safely migrate away from zcashd. We think the focus over the coming weeks should be on making that transition as smooth and secure as possible.