Arborist Call #106 | R&D Summary (07/24/2025)
Core Team Updates, Research & Implementation Updates, Open Announcements & Discussion.
The Zcash Arborist Calls are bi-weekly protocol development meetings focused on tracking upcoming protocol deployment logistics, consensus node implementation issues, and protocol research.
This summary focuses on the last call that took place on 07/24/2025
Zebra v2.4.0 introduced a DB format upgrade but had a bug, fixed in v2.4.1.
CI + test infra getting major improvements to catch these earlier. Heads up if you ran zebra v2.4.0 please follow the recovery recovery steps.
Zebra cleanup: removed unused crates like zebra scan & zebra grpc
Refactoring to rely more on zcash primitives (esp. tx building)
PRs in flight: NU6.1 support, QI test infra, librustzcash & more
Merging of external PRs and tackling open tickets
Big updates from the ECC core team post-ZEC Summit:
Zcash is entering a new chapter NU6.1 is targeted for October, wrapping the current lockbox stream. Disbursements will go to P2SH multisig which means wallets like Zashi & Keystone need to step up with full support. We're finally seeing practical FROST + quantum.
Seeing major momentum:
Compact blocks may soon include transparent info (improves metadata privacy) A post-quantum key (qSk) is being drafted to future proof hardware wallets Zashi is reworking Tor options to better support users in risk regions.
Most people aren’t watching, but the Zcash dev stack is heating up.
Librustzcash PRs flowing FROST specs maturing P2SH going mainstream.
Zaino’s shaping up fast , major refactor now supports both finalized & non-finalized chain states. Built for crosslink from day one. Light wallet proxy may hit production in 2 weeks. Clean, forward-compatible design.
Zcashd Deprecation is moving but visibility across teams has been a bit opaque. Pacu’s stepping in to build a lightweight, no deadline tracking tool to surface progress. Not about pressure, just clarity. Feels overdue. Let’s make the unseen work visible.
Progress on ZSA continues across, Encoding updates for better versioning & signature clarity Design tweaks applied to Python ref impl, test vectors, & ZIPs Orchard & librustzcash catching up with upstream Clean circuit refactors & simplification underway Steady hands on NU7.
A follow-up PR was opened on top of Shielded Labs’ librustzcash work (ZIP 233) due to cross-org push limits. Review is active, ECC plans to accept suggestions. No extra work needed from Mariusz smooth handoff and solid momentum.
Zcash test vectors PR (a blocker for ZIP 233) was meant to be merged just slipped through the cracks. Arya (ZF) or Mark (Shielded Labs) may assist. Once resolved + rebase done, ZIP 233 merge should be within reach.
Crosslink milestone 3 is active: PoW blocks now anchor to BFT blocks. No staking or rewards yet just a hardcoded finalizer set. Design work is shifting toward full PoS logic for milestone 4. Hybrid finality in motion.
Design discussions heating up!
How do we reward finalizers without bloating the chain or weakening security? BFT signature schemes, old TFL concepts, and fresh proposals are all on the table. Coordination call coming.
Josh proposed that after NU7, each org maintain its own Zebra fork and handle full dev for its proposed changes. Jason raised it on the Arborist Call to get ZF & community feedback before Shielded Labs responds.
ZF, ECC, and others clarified: forks = development tools, not competing nodes. Still, concerns were raised about CI complexity, coordination overhead, and how unclear roles might slow not speed upgrades.
Arya said the decentralization proposal is “non-controversial” if forks aren’t releasing their own versions. She supports the idea of each org gaining deeper familiarity with Zebra and other core crates through forking.
The call ended with general agreement:
Decentralization is necessary.
Fork must not become chain splits.
Coordination and clear process are critical
A follow up post with clarified messaging is needed.
