Zcash Ironwood Upgrade: What Changes on July 28

July 28 is a real line in the sand for Zcash. Ironwood is switching on, and a lot of behind-the-scenes plumbing changes the way shielded ZEC moves. If you run a node, operate a wallet, or just hold some ZEC in a personal app, you probably want the short version of what breaks, what keeps working, and what to do next.

The quick headline: a new shielded pool comes online with a guarded bridge called a turnstile. The old Orchard pool stops accepting new outputs. And the legacy zcashd client has already tapped out, so Zebra is the way forward for nodes.

Let’s walk through it cleanly so you can make a plan, not scramble at the last minute.

Aspect What to Know Activation Ironwood (NU6.3) is set to activate at mainnet block 3,428,143, expected around 13:00 UTC on July 28, per Zebra 6.0.0 release notes Zcash Foundation (Zebra 6.0.0 release). Client support zcashd reached end of support on July 18 at block 3,417,100 and refuses to restart ahead of NU6.3. Run Zebra 6.0.0 or newer The zcashd Book (Zcash docs). Shielded pools Orchard is retired for new deposits and outputs after activation. A new Ironwood shielded pool takes over for fresh shielded activity crypto.news (coverage of Ironwood/NU6.3 deployment). Turnstile A constrained bridge controls value leaving Orchard and entering the new pool, enabling independent supply checks after the Orchard vulnerability crypto.news (coverage of Ironwood/NU6.3 deployment). Testnet Testnet activation completed July 4 at block 4,134,000, so most tooling had a dress rehearsal The zcashd Book (Zcash docs). Impact on users Stop using Orchard addresses for new receipts. Update wallets that add Ironwood support. Plan migrations after activation if you still hold Orchard notes. Risk surface Outdated software, stuck deposits to Orchard, and mismatched wallet versions are the main hazards around activation.

Editor's note: In Q2 2026 I watched a couple of custody desks quietly spin up parallel Zebra nodes weeks before Ironwood and run dark traffic through them. That dry-run approach saved them during testnet activation on July 4, when one vendor discovered a subtle wallet indexing issue. By mid-July, I also saw smaller OTC desks get caught flat-footed by the zcashd shutdown at block 3,417,100 and scramble for Zebra support. The lesson I took into July 28 is simple. Treat activation like a change window, stage migrations, and do a small live send before reopening deposits. — Elliot Veynor

Zcash upgrades run at specific block heights, which means the network flips new rules on all at once. With Ironwood, the big shift is how shielded value is accounted for. The existing Orchard pool that carried private ZEC for years is being sunset for fresh activity, and a brand new pool takes the baton for new transactions.

To keep supply accounting tight, value cannot just slide from Orchard into the new pool unchecked. That is the point of the turnstile. It is a controlled path that puts a cap on how funds leave Orchard and appear in the Ironwood pool, so third parties can independently compare totals and spot anomalies. After the Orchard vulnerability, this design is the belt and suspenders approach many were asking for crypto.news (coverage of Ironwood/NU6.3 deployment).

All of this only works if nodes and wallets speak the same rules on day one. Zebra 6.0.0 set the mainnet activation height to 3,428,143 and shipped on July 10, so operators have had a few weeks to update Zcash Foundation (Zebra 6.0.0 release). On the testing side, NU6.3 hit testnet July 4 at height 4,134,000, which helped vendors run final checks The zcashd Book (Zcash docs).

Key terms, briefly

• Ironwood The codename for Zcash’s NU6.3 network upgrade that introduces a new shielded pool and turnstile rules.
• Activation height The exact block where new consensus rules take effect. For Ironwood, that is 3,428,143 on mainnet per Zebra 6.0.0.
• Orchard The existing shielded pool being retired for new outputs once Ironwood activates. Existing Orchard notes can still be migrated via the turnstile path.
• Shielded pool The cryptographic accounting space where private ZEC transactions live. Ironwood introduces a fresh pool for new private activity.
• Turnstile A controlled migration mechanism that constrains and tracks value leaving Orchard and entering the new pool for supply verification.
• Zebra The Zcash Foundation’s full node client. Version 6.0.0 configures Ironwood activation and is the supported path for mainnet post-zcashd EOL.

Step-by-Step Playbook

1. Confirm your software If you run a node or wallet backend, check the version. zcashd 6.20.0 has reached its end of support and will not carry you through NU6.3 The zcashd Book (Zcash docs).
2. Upgrade to Zebra 6.0.0 or newer Install and sync a Zebra node that sets the activation height to 3,428,143. Do this before July 28 so you hit the switch cleanly Zcash Foundation (Zebra 6.0.0 release).
3. Pause new Orchard deposits Stop giving out Orchard addresses for incoming funds. After activation, new outputs to Orchard are retired by consensus and will not behave as expected.
4. Back up your wallet data Export seeds and any wallet metadata. If your wallet tracks Orchard notes, ensure you have a reliable snapshot before you start any migration.
5. Test a small post-activation transaction Once the new rules are live, send a tiny amount in the new shielded pool to confirm your stack is wired correctly.
6. Plan your Orchard migrations If you hold Orchard notes, schedule moves through the turnstile after activation. Follow your wallet’s guidance since implementations may stage this in batches.
7. Monitor mempool and confirmations Early after activation, watch for any odd backlog. Give yourself extra confirmations for critical transfers until the network settles.
8. Communicate with counterparties If you operate an exchange or custodian, update status pages so users know which address types you accept and any maintenance windows.

What actually changes for everyday users

If you mostly send and receive ZEC in a consumer wallet, the biggest visible change is where your private funds live. New shielded transactions are created in the fresh Ironwood pool. Wallets that stay current will either auto-migrate or give you a one-click flow to move any remaining Orchard notes via the turnstile. Expect a little UI churn as developers surface the new address types and warnings.

Transparent addresses remain what they’ve always been. The shift is squarely in shielded land. The network has already tested this path on testnet since July 4, which reduced the odds of UX surprises, but day one can still be quirky on certain apps The zcashd Book (Zcash docs).

Privacy semantics stay aligned with Zcash’s goals. The reason the turnstile exists is supply verifiability, not to water down privacy. It constrains the accounting edges between pools so auditors can reconcile totals after the Orchard vulnerability, as covered in July’s rollout notes crypto.news (coverage of Ironwood/NU6.3 deployment).

For node operators and services: Zebra vs the old stack

The path forward is clear. zcashd has halted. Zebra is maintained and configured for Ironwood. If you are running infra, the question is how Zebra fits your operational habits. The good news is activation timing was published on July 10, giving a reasonable window to deploy and observe a full sync in staging Zcash Foundation (Zebra 6.0.0 release).

Factor Zebra (current) zcashd (legacy) Support status Actively maintained for NU6.3 and beyond Reached end of support July 18 at height 3,417,100; auto-shutdown behavior before Ironwood The zcashd Book (Zcash docs) Activation readiness Activation height 3,428,143 baked into 6.0.0 Will not run through NU6.3 activation Configuration Modern config patterns and telemetry options Deprecated config surface, no future updates Ecosystem focus Foundation-led client with current docs Historical client, now frozen Migrations Recommended target for exchanges and custodians Requires moving off to maintain service

Pro tip: spin up a fresh Zebra alongside your existing stack, sync it fully, and point a single wallet instance to it for a dry run. Treat activation day like a maintenance window, not an all-at-once flip.

Edge cases and migration scenarios to think through

Got a cold wallet that last synced months ago. Sync it before activation so it learns the final Orchard state under the old rules. That makes post-activation reconciliation smoother.

If you operate an exchange, be clear about address types during the cutover. Temporarily disabling shielded deposits for a few hours around activation can save your support queue, then re-enable with the new address format once your backend confirms it is mining post-3,428,143 blocks. Communicate this plan ahead of time wherever you surface deposit instructions.

For power users with many Orchard notes, do not rush everything through at once. The whole point of the turnstile is controlled flow. Batch migrations in wallet-defined sizes, log txids, and verify balances after confirmations. If your wallet supports labels, tag each movement so auditing later is trivial.

Pitfalls & Red Flags

• Running zcashd past July 18 The client auto-halts and will not carry you through activation. You risk ending up on a dead end service if you ignore this The zcashd Book (Zcash docs).
• Sending to Orchard after activation New Orchard outputs are retired. Using an old address on or after July 28 can cause failed deposits or funds that do not appear where you expect.
• Unpatched wallets Apps that have not shipped Ironwood support may mis-handle balances or get stuck resyncing. Wait for a version that explicitly mentions NU6.3 readiness.
• Skipping backups Migrating shielded funds without a fresh seed and metadata backup is asking for trouble if something crashes mid-process.
• Assuming instant finality Early after activation, give more confirmations than usual for high-value moves until network conditions stabilize.
• No audit trail If you are moving many notes, keep a simple spreadsheet or note with txids and amounts so you can reconcile later.

If you want more clear, plain-English explainers like this as upgrades land, we cover them daily at Crypto Daily.

Frequently Asked Questions

When exactly does Ironwood activate on mainnet

The activation height is 3,428,143. Based on current block times, that lines up around 13:00 UTC on July 28, per Zebra 6.0.0 release notes Zcash Foundation (Zebra 6.0.0 release). Always trust your node’s height and the actual chain, not a wall clock.

Do I need to move my funds out of Orchard right away

No one is forcing an instant migration, but you should stop using Orchard addresses for new receipts once Ironwood is live. Plan to move any remaining Orchard notes via the turnstile path using an updated wallet so supply accounting stays consistent.

What happens if I keep running zcashd

zcashd 6.20.0 hit its end-of-support halt on July 18 at height 3,417,100 and refuses to restart ahead of NU6.3. You need Zebra 6.0.0 or later if you want to observe or validate post-activation blocks The zcashd Book (Zcash docs).

Are transparent addresses affected by Ironwood

Transparent addresses remain unchanged by this upgrade. The major changes apply to shielded pools, retiring new outputs in Orchard and introducing the new Ironwood pool.

Why is there a turnstile at all

It is there to constrain and account for value moving from Orchard into the new pool, enabling independent verification of total ZEC supply after the Orchard vulnerability discussed in rollout coverage crypto.news (coverage of Ironwood/NU6.3 deployment).

Was this tested before mainnet

Yes. NU6.3 activated on testnet July 4 at height 4,134,000, which gave clients and services a live rehearsal under the new rules The zcashd Book (Zcash docs).

Will fees or confirmation times change

There is no specific fee change tied to activation. As with any major upgrade, the first few hours can see choppy mempools while services adjust. Plan for extra confirmations if your transfer is sensitive.

Disclaimer: This article is provided for informational purposes only. It is not offered or intended to be used as legal, tax, investment, financial, or other advice.