Key Takeaways:
🔸 NU7 Preparations: Zebra advances mining optimizations, while developers discuss a specification discrepancy that could reduce total ZEC issuance by approximately 0.67 ZEC.
🔸 Zodl Infrastructure: Progress on librustzcash, Zallet, and NU7 compatibility, alongside the release of Lightwalletd v0.5.5 and pasta_curves v0.6.1.
🔸 Zcash Shielded Assets: QEDIT completes NU6.3 compatibility work across Orchard, librustzcash, and Zebra, preparing for further integration and review.
🔸 Crosslink: Shielded Labs successfully activates BFT finality on FeatureNet, releases node software v15, and continues incentivized testing.
🔸 Dynamic Fees: Developers advance fee estimation proposals while discussing interoperability concerns between Zebra and Zakura.
🔸 Formal Verification: Verified Pasta Curves arithmetic implementations strengthen assurance around critical cryptographic operations.
🔸 Post-Quantum Research: Akita and Ragu research progresses, while Shielded Labs introduces EPOCH, its new post-quantum cryptography team.
NU7 Preparations and Issuance Discussion
Preparations for NU7 continue across the Zcash development ecosystem.
The Zcash Foundation’s Zebra team is working on mining pool optimizations ahead of the upgrade, while other development teams continue preparing their software for the upcoming protocol changes.
The team expects the NU7 activation height to be determined by October 20.
However, developers also identified a discrepancy between ZIP 218 and ZIP 237 that could result in approximately 0.67 ZEC less total issuance.
The discussion focused on whether the rounding discrepancy should be corrected before NU7 activation or addressed in a future network upgrade.
No final decision was announced during the call.
Although the potential difference is relatively small, ensuring consistency between protocol specifications remains important for maintaining the integrity of Zcash’s monetary rules.
Zodl Advances Wallet and Infrastructure Development
Zodl continues preparing its software for NU7, with ongoing work across librustzcash, Zallet, and other components of the Zcash development stack.
The team has advanced librustzcash pre-releases, improved zcashd compatibility, and reviewed specifications related to NU6.3, NU7, and the Network Sustainability Mechanism (NSM).
These efforts help prepare the underlying software used by Zcash wallets and applications for the upcoming upgrade.
Zallet and Zaino
Zodl is preparing a new Zallet release for the NU7 testnet, with mainnet support planned afterward.
The Zaino backend has been temporarily removed from Zallet following discussions with Zingo Labs.
This allows both teams to continue their backend development before reintegrating Zaino.
Lightwalletd v0.5.5
Lightwalletd v0.5.5 has been released with improvements to backend reliability and monitoring.
The update fixes backend failures and introduces a metric that helps operators identify when their servers are falling behind the latest blockchain state.
The Docker image has also been reduced by approximately 90%, making deployments more efficient.
Cryptographic Performance Improvements
Zodl released pasta_curves v0.6.1, introducing optimized assembly implementations for AArch64 and x86-64 processors.
These changes improve the performance of arithmetic operations used in Zcash’s cryptographic infrastructure.
The team also continued work on signing support and Ledger-related libraries.
Zcash Shielded Assets Move Forward
QEDIT reported another milestone for Zcash Shielded Assets (ZSAs).
The team completed NU6.3 compatibility work across Orchard, librustzcash, and Zebra, bringing the implementation in line with recent network upgrades.
ZSAs are designed to extend Zcash’s shielded transaction capabilities to assets beyond ZEC.
QEDIT is now preparing to move its implementation into dedicated branches within the main Zcash repositories.
To simplify technical review, Orchard circuit changes have been separated into upstream PR #506.
The broader implementation has undergone external auditing, but ZSA activation has not yet been decided.
This work represents continued progress toward integrating shielded assets into the Zcash protocol.
Crosslink Demonstrates BFT Finality on FeatureNet
Shielded Labs reported significant progress on Crosslink, a proposed mechanism designed to provide an additional layer of transaction finality for Zcash.
Following a successful FeatureNet restart on October 1, Crosslink bootstrapped Byzantine Fault Tolerant (BFT) consensus and began finalizing blocks.
In practical terms, this means the experimental network successfully demonstrated the finality mechanism that Crosslink is being developed to provide.
FeatureNet Testing
The current testing configuration includes:
12 active finalizers
10% finalizer commissions
A three-day staking interval
Shielded Labs also distributed 25 ZEC during its second round of incentivized testing.
These tests help evaluate how finalizers participate in the network and how the proposed incentive system behaves.
Crosslink v15 Released
Shielded Labs released Crosslink node software v15, introducing fixes for a BFT consensus edge case, finalizer commission issuance, and bond denomination rules.
The changes are part of a small FeatureNet network upgrade.
Crosslink remains in development, but these results represent progress toward testing its finality mechanism under more realistic network conditions.
Dynamic Fees and Transaction Interoperability
Developers continued discussing improvements to Zcash’s transaction fee system.
Shielded Labs is preparing a detailed ZIP for its proposed dynamic fee estimation mechanism.
The team is also encouraging wallet developers to support the getStandardFees RPC and a priority fee lane.
These features would help wallets estimate transaction fees and allow users to pay higher fees when appropriate.
However, the discussion also raised questions about consistency between different node implementations.
A reported 400-zatoshi marginal fee setting in Zakura prompted concerns about whether transactions would be handled consistently across the network.
Daira noted that transactions paying insufficient fees could encounter interoperability problems.
The Zebra team had not yet determined how to handle the difference.
Maintaining consistent fee behavior will be important as Zcash continues developing more flexible transaction fee mechanisms.
Formal Verification Advances
Formal verification remains an active area of research and development within Zcash.
This process uses mathematical methods to verify that software behaves according to its intended specifications, providing additional assurance for security-critical code.
During the call, Daira reported verified arithmetic implementations for the Pasta Curves, including optimized multiplication and inversion operations.
The work is particularly relevant because cryptographic performance improvements must preserve the correctness of the underlying calculations.
Research also continues across other areas of Zcash cryptography, including:
Orchard and Ironwood circuits
Halo 2 security properties
Balance integrity
Future verification of spendability
Shielded Labs is also exploring Quint modeling for its zero-indexer tooling.
These efforts contribute to a broader goal of strengthening the reliability and security of Zcash’s cryptographic infrastructure.
Post-Quantum Research: Akita and Ragu
Post-quantum cryptography was another major research topic.
Daira discussed Akita, a lattice-based polynomial commitment scheme being evaluated for possible integration with Ragu.
The research explores cryptographic approaches intended to remain secure against future quantum computing threats.
Early estimates suggest proof sizes of approximately 85–90 KB, although additional security analysis and design work are still required.
One of the main challenges is balancing stronger cryptographic security with practical network performance.
Larger proofs can increase the amount of data that transactions require, making efficiency an important consideration for future protocol designs.
Shielded Labs Introduces EPOCH
Shielded Labs also introduced EPOCH, a new team focused on post-quantum cryptography research.
Led by cryptography researcher Ulrich, the team will investigate post-quantum proof systems, digital signatures, and broader protocol design.
A central challenge will be understanding how Zcash could adopt larger post-quantum cryptographic proofs while maintaining practical network throughput.
The initiative adds another research effort focused on Zcash’s long-term cryptographic security.
Looking Ahead
The October 15 Arborist Call highlighted progress across several areas of Zcash development.
NU7 preparations are moving forward, although developers are still evaluating an important specification discrepancy. Zodl continues improving wallet infrastructure, while QEDIT is preparing further integration work for Zcash Shielded Assets.
Crosslink has demonstrated BFT finality on its FeatureNet, and ongoing discussions around transaction fees aim to improve consistency across node implementations.
Meanwhile, formal verification and post-quantum research continue exploring ways to strengthen the security of Zcash’s cryptographic systems.
Together, these developments show how work on immediate network upgrades is progressing alongside longer-term research into the future of the protocol.
Next Arborist Call
The next Zcash Arborist Call is scheduled for November 12, 2026.
The October 29 call has been canceled due to Zcon7.
For more information, visit the Zcash Arborist website.