Zcash Network Upgrade 6.1 Is Live — Here's What It Brings

The Zcash ecosystem continues to evolve, and the latest milestone — Network Upgrade 6.1 (NU6.1) — is now live on testnet.

We’re excited to share that our RPC infrastructure has already been fully upgraded to support NU6.1. In this post, we’ll walk you through what’s new, why it matters for developers and builders, and what this means if you’re running on our infrastructure.

Why NU6.1 Is an Important Upgrade

This isn’t just a protocol update — NU6.1 makes important changes that improve the developer experience, governance structure, and overall network sustainability.

1. Developer Tools Get More Accurate

A long-standing issue with balance tracking in RPC methods is finally resolved. Orchard unshielding transactions are now properly reflected in methods like getbalance and gettransaction.

2. Transaction Formats Are Moving Forward

The default transaction version is now v5, which was introduced with NU5. It’s more extensible, better supported, and aligns with the modern Zcash roadmap.

3. Governance Becomes More Inclusive

ZIP 1016 brings more coinholder and community participation into Zcash’s funding model — a step toward more decentralized decision-making.

What’s Included in NU6.1

ZIP 271: Deferred Dev Fund Lockbox

Zcash now defers and structures the disbursement of development funds, allowing for more transparency and security in how funding is handled.

ZIP 1016: Community and Coinholder Funding Model (Partially Live)

This ZIP gives coinholders and the broader community a say in how development resources are allocated. While this is only partially implemented for now, it’s an important first step.

Testnet Activation & Regtest Config

NU6.1 is already active on testnet at block height 3,536,500. If you’re testing locally or integrating with regtest, you can activate NU6.1 using the following parameter:

-nuparams=4dec4df0:HEIGHT

Note: As with previous upgrades, some rules may still be tweaked before mainnet activation. If so, testnet will be rolled back and re-activated in version 6.10.0. For more details, see ZIP 255.

Orchard RPC Bug Fix

Before this upgrade, RPC methods that calculate balances and fees didn’t fully support transactions that unshielded funds from the Orchard pool.

This bug caused inconsistencies for wallets and explorers using getbalance, gettransaction, and related methods. With NU6.1, those issues are resolved.

What’s fixed:

• Orchard unshielding is now correctly recognized

• Balances are accurate across shielded and transparent pools

• Transaction fees are properly included

This fix brings Orchard in line with Sprout and Sapling, which had similar issues resolved earlier.

Transaction Version Update

Zcash nodes now default to using transaction version 5.

• Old default: -preferredtxversion=4 (used since Sapling in 2018)

• New default: -preferredtxversion=5 (introduced with NU5 in 2022)

If you're still using v4 for compatibility reasons, you can override the default with:

-preferredtxversion=4

We’ve Already Upgraded

Our RPC infrastructure has been fully updated to support all NU6.1 changes. That means:

• You’re already using NU6.1-compatible RPC endpoints

• Transparent and shielded balances are reported accurately (including Orchard)

• Your apps will benefit from modern transaction support (v5 by default)

No action is required on your side if you're using our service — but if you’re building tools or wallets, this is a great time to start testing against the updated protocol.