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 11/06/2026
Highlights
A busy call covering security, infrastructure, wallets, and protocol research across the Zcash ecosystem.
Zebra shipped multiple releases following recent security updates.
Zallet Alpha 4 moves closer to launch with zcashd migration features.
Late July remains the target for the final stages of zcashd deprecation.
Ironwood development and formal verification efforts continue to advance.
The future deprecation of the Sprout pool was also discussed.
Let's dive in.
The Zebra team has had a busy few weeks with several releases focused on security and network maintenance.
Zebra v4.5.0 was released on May 29, addressing security issues identified through the bug bounty program.
A follow-up patch was released shortly after to address additional security findings.
On June 2, the team implemented a soft fork to deactivate the Orchard pool as part of a publicly disclosed security response.
NU6.2 activated on June 3, re-enabling the intended fixes and bringing the network to its current operational state.
Alongside the recent upgrades, the Zebra team investigated a chain synchronization bug that could cause nodes to stall while syncing.
A fix was released on June 10 to resolve the sync stall issue and improve node reliability.
Another patch release is expected soon. In addition to correcting support date information, it will include an increase to the reorg window to reduce an identified area of exposure and further strengthen network resilience.
The team’s focus remains on security hardening, sync reliability, and maintaining a stable network following the recent NU6-related updates.
Following the successful NU6.2 network upgrade, the Zodl team has been focused on Zallet Alpha 4, with a release expected in the coming days.
Key additions include:
Sync engine refactor
Full block scanning
Coinbase RPC support
GetWalletStatus RPC
The release also brings major progress toward zcashd migration and broader wallet compatibility.
The upcoming Zallet Alpha 4 release will include support for importing zcashd wallet data, including:
Watch-only addresses
Private keys
P2PKH addresses
Sapling keys
This will allow existing zcashd users to test migration paths into Zallet more easily.
The team also improved integration testing, completed a zcashd regtest wallet builder, and implemented full transparent coin tracking in zcash_client_backend.
Additional work completed over the last two weeks includes:
NU6.2 follow-up updates
Orchard crate upgraded to v0.14.0
New Zallet RPCs merged, including key import/export functionality
JSON-RPC cookie file support
Pacu also thanked contributors across the ecosystem for their coordination during the recent security response, including recognition for Taylor's responsible disclosure that helped drive the remediation effort.
“Everybody did a great job last week.” Pacu
The Zcash ecosystem is targeting late July as the finish line for zcashd deprecation, aligning with the planned transition from Orchard to Ironwood.
Several parallel efforts are helping make that possible:
Continued Zodl development
Ongoing Zebra improvements
Zaino performance enhancements
Infrastructure migration support for ecosystem partners
The goal is a smooth transition to the next generation of Zcash infrastructure.
Progress is coming from multiple teams across the ecosystem.
New Zodl engineer Danny Williams received recognition for rapidly contributing and closing PRs during his first week.
Valar Group is building a compatibility wrapper around zcashd to help organizations that cannot immediately migrate to newer infrastructure. A testnet version is expected soon.
The Zaino team is improving performance with database optimizations and exploring a lightweight mode that allows faster deployment of Zaino instances.
Community members are encouraged to test Zallet, import zcashd wallet backups, and provide feedback as preparations continue for the final stages of zcashd deprecation.
Judah provided a brief update on the Network Sustainability Mechanism (NSM) work.
The ZIP 234 PR was released last week and is currently awaiting review.
Work is also underway on a ZIP 235 bug-fix PR, which will incorporate additional findings from a recent code audit.
The audit surfaced a few extra items that the team plans to address before the next PR is submitted, helping further strengthen the NSM implementation.
Crosslink FeatureNet Updates
Nate shared updates from Crosslink's second FeatureNet-era workshop.
The team experimented with a more conversational format and saw encouraging participation, including at least five new attendees joining for the first time.
One challenge identified is onboarding. As the network becomes more persistent, syncing new users during live workshops takes longer than it did when networks were ephemeral.
The team is exploring better ways to welcome and support newcomers while continuing to share technical updates.
Shielded Labs has completed a scanning tool that will be used to distribute Mainnet ZEC rewards to FeatureNet participants.
Participants who wish to receive rewards must submit:
A Crosslink testnet viewing key (with the "test" prefix)
A Mainnet ZEC address
The submission deadline is June 17.
The rewards system calculates participation based on testnet activity such as mining and staking rewards. During testing, the team encountered long-running chain forks exactly the type of issue Crosslink's trailing finality mechanism is designed to address.
As Nate noted, this has become a real-world opportunity to test and improve the technology under development.
Progress continues on Dynamic Fees, including the first successful "canonical" priority fee transaction sent through a wallet interface rather than custom tooling.
Current network data shows two major fee groups:
Users paying the ZIP 317 recommended 5,000 zats
Users paying significantly higher fees, sometimes exceeding 100,000 zats per action
The goal is a more predictable fee market with a dedicated priority lane for users who need faster confirmations.
Work is underway on proposals that would:
Reduce the marginal fee from 5,000 to 1,000 zats
Increase the weight ratio cap from 4x to 10x
Feedback from wallet developers continues to shape the design. Rather than implementing Replace-By-Fee (RBF), discussions focused on using short transaction expiries combined with priority fees to achieve similar user outcomes while maintaining a simpler and more predictable experience.
Ecosystem Collaboration & Ironwood
One of the recurring themes throughout the past few weeks has been the strong collaboration across teams during the response to the recent security issue.
Contributors from multiple organizations worked closely with miners and ecosystem partners to coordinate mitigations and network upgrades.
The effort was widely praised as an example of effective ecosystem-wide cooperation.
Ironwood & Formal Verification
Work on Ironwood continues across protocol design, cryptography, security assurance, and formal verification.
Teams have been aligning on protocol rules while advancing formal verification efforts aimed at strengthening confidence in future implementations.
Current work includes modeling cryptographic components, validating them against test vectors, and formalizing key protocol security properties.
Community & Education
The next protocol walkthrough is scheduled for June 16 at 3 PM UTC on the Zcash Global Discord.
The session will focus on Merkle Trees and is open to anyone interested in learning more about Zcash protocol fundamentals.
Community members interested in formal verification efforts were also invited to participate in ongoing coordination discussions.
Sprout Deprecation Discussion
Discussion continued around the future of the Sprout pool, with growing support for eventually retiring it.
Community members holding funds in Sprout were encouraged to move them sooner rather than later. As the ecosystem transitions away from zcashd, future wallet support for Sprout transactions is expected to become increasingly limited.
If you still have funds in Sprout, now is a good time to begin planning a migration.