Zcash NU7 explained: what changed at block 3,543,405, and what you need to do.

NU7 went live at block 3,543,405 on November 6, 2026 at 02:34 UTC. Here is what it changed, what it left alone, where every number comes from, and the one thing you need to do.

NU7 is the Zcash network upgrade that activated at block 3,543,405 on November 6, 2026 at 02:34 UTC. It cuts the block target from 75 seconds to 25, keeps new ZEC per day and the 21M cap where they were, sends 60% of each block's fees to a reserve that pays back out from 2031, and gives Ironwood, the main private pool, more than twice the room. If you hold ZEC, the one thing to do is update your wallet app.⁰¹

Below, one change at a time: why each number is what it is, and what it means for holders, node runners and anyone moving ZEC. Every figure traces to a primary source: the ZIPs (Zcash Improvement Proposals, the network's written specs), the node releases, block timestamps or the vote tallies. Start with the 50-second version.

What is Zcash NU7?

NU7 is a Zcash network upgrade: a set of rule changes every up-to-date node switched on at the same block. It's a small one by design, deployed by ZIP 259, with no new transaction format and no new address type.⁰¹ Everything it changes fits in one table.

ZIP 259 deploys seven ZIPs together: ZIP 218 (25-second blocks, plus per-block limits on private transactions), ZIP 235 (60% of fees to a reserve), ZIP 237 (how that reserve pays back out without moving the halvings), ZIP 2003 (v4 transactions switched off), and three pieces of funding-stream bookkeeping: ZIP 2008, ZIP 207 Revision 2 and ZIP 214 Revision 3.⁰¹⁰⁸ The sections below take them one idea at a time.

When did NU7 activate?

NU7 activated at block 3,543,405 on November 6, 2026 at 02:34 UTC, which was Thursday evening, November 5, US time. The height was fixed on October 21, when the ZIP editors merged it into the spec.⁰⁷ The clock time never was: Zcash upgrades trigger at a block height, not a date, so the exact minute depended on how quickly miners found the blocks before it.

Two details for the people who check these things. From that block on, every transaction signature commits to a new consensus branch ID, 0x77190AD9: a tag that says which set of rules the transaction was signed for. It replaces NU6.3's 0x37A5165B.⁰¹⁰⁹ And the height factors as 3 × 1,181,135. That's deliberate. ZIP 259 says the activation height MUST be a multiple of 3, because the funding-stream rules in ZIP 214 Revision 3 rescale their schedules for three times as many blocks.⁰¹⁰⁶

Do I need to do anything with my ZEC?

For most holders, one thing: update your wallet app. Same addresses, nothing to move. No NU7 ZIP changes an address format or adds a transaction format, and the NU7 timeline post on the Zcash Community Forum said it plainly: "The changes in this upgrade should not affect wallets in any significant way."²⁰ The Zodl wallet (formerly Zashi), for one, shipped NU7 support in Android version 3.19.0 on October 29.²²

Why update at all? From activation, wallets must stop building version 4 (v4) transactions, an older format NU7 switches off, and sign with the new branch ID.⁰¹ An app that hasn't shipped an update may not be able to send ZEC until it does. Your coins stay where they are on-chain. If an out-of-date app can't send, the app is what's stuck, not your ZEC.

Three edge cases:

• Signed before activation, never mined. A transaction that wasn't mined by block 3,543,404 is invalid now, because its signature commits to the old branch ID. Rebuild it and sign again. The same goes for saved or offline-signed transactions.⁰¹
• Exchange pauses. Exchanges and swap services may pause ZEC deposits and withdrawals briefly around an upgrade. If yours did, check its notice for when they resume.
• Sprout. Funds in Sprout, Zcash's original 2016 private pool, are the one exception to "nothing to move": they can't be moved at all now. More on that below.

Zcash blocks now target 25 seconds

Zcash now aims for one block every 25 seconds, down from 75. That's ZIP 218. Zcash has cut the target once before: the Blossom upgrade halved it from 150 seconds to 75 in December 2019. The effect for users is the one ZIP 218 names: "The user-visible latency goes down 3x." Once block times settle, a first confirmation takes about 25 seconds on average instead of about 75.⁰²

First, the target isn't hit at the activation block. NU7 also widens the difficulty averaging window from 17 blocks to 102, so difficulty is smoothed over the same 2,550 seconds it was at Zcash's launch (102 × 25 = 17 × 150). ZIP 218 expects blocks right after activation to arrive about 57 seconds apart, and the wider window takes roughly six times as many blocks to settle as the old one would have.⁰² That works out to a few hours. If your first post-NU7 transaction waited closer to a minute, that's why.

Second, more frequent blocks don't change how many confirmations an exchange or swap venue waits for, and a swap also waits on the other chain. ZIP 218 says it "does not argue for clients reducing confirmation counts".⁰² Each venue sets its own policy.

Does NU7 change ZEC supply, halvings or the 21M cap?

Not the issuance schedule, the halvings or the cap: about 1,800 new ZEC are still issued a day, the 21M cap holds, and the next halving lands on the same projected day. Three times as many blocks would mean three times the issuance if nothing else changed, so ZIP 218 divides the block reward by three and triples the halving interval to 5,040,000 blocks. The reward drops from 1.5625 ZEC to 0.52083333 ZEC (52,083,333 zatoshi).⁰²⁰⁶ At the target pace that's 1,152 blocks a day before and 3,456 after, or about 1,800 new ZEC a day either way. "About", because real block times wander around the target.

"Block reward" here means all the new ZEC in a block. About 20% of it goes to Zcash's funding streams, which fund Zcash development, and the miner gets the rest.⁰⁶ For the decimal-minded: three new rewards add up to 1.56249999 ZEC, one zatoshi short of one old reward, because 156,250,000 zatoshi doesn't divide evenly by 3.

The Zcash Foundation's release post puts it in one line: "The four year halving schedule and the 21 million ZEC supply cap are both unchanged."¹⁴ The next halving was due at block 4,406,400. Under NU7 it moves to block 6,132,390 (ZIP 259 derives it as 13,219,200 − 2 × 3,543,405), which lands on the same projected day, around November 24, 2028.⁰¹

Where do Zcash fees go now?

Since NU7, 60% of the fees in every block, rounded down, are removed from circulation and placed in a reserve. The miner keeps the other 40%, a hair more after rounding. NU7 doesn't change what you pay; it changes where 60% of it goes. That's ZIP 235.⁰³¹⁴

ZIP 237, part of what Zcash calls the Network Sustainability Mechanism, decides what happens to the reserve. Starting at block 8,939,664, around February 2031 at 25-second blocks, every block pays out a fixed fraction of the reserve (1,375 parts in ten billion) as extra block reward. At that rate a balance with nothing added would halve about every four years, so the reserve pays back out slowly, not all at once. Part of every fee now funds future block rewards. The reserve didn't start at zero, either: NU7 seeded it with 368.58445520 ZEC of block rewards and fees that miners left unclaimed before NU6.⁰⁴⁰¹

The 2031 date is where the polls split. Coinholders chose February 2031 with 96.6% of the ZEC cast.¹⁸ Community panels preferred "as soon as possible", and ZIP 259 records that the polls "did not reach a shared majority position" on the date. The five organizations coordinating NU7 (Shielded Labs, Project Tachyon, ZODL, the Zcash Foundation and Valar Group) then aligned on February 2031.¹⁹⁰¹

What happened to Sprout?

Sprout funds can't be spent anymore. ZIP 2003 disables version 4 transactions: from NU7, "The transaction version number MUST be 5 or 6." Sprout, Zcash's original 2016 private pool, can only be spent with v4. So the roughly 22,300 ZEC still in it, about 0.4% of all shielded ZEC as of October 21, is now frozen.⁰⁵⁰²

Frozen, not gone. That ZEC "remains issued" and still counts in Zcash's issued supply. Nobody can move it under current rules, and ZIP 2003 says the ability to spend Sprout funds "may never be re-enabled".⁰⁵ The coinholder poll backed switching v4 off at NU7 rather than later.¹⁸

The v4 change reaches past Sprout. It covers every v4 transaction, transparent and Sapling ones included. Any wallet or signing library that still builds v4, or still signs for NU6.3's branch ID, can't produce a transaction the network accepts until it's updated.⁰¹

More room in the main private pool

Ironwood, the main private pool, goes from about 2.9 to at most 6.6 transactions a second, more than twice the room. Ironwood arrived with NU6.3 in July 2026, and ZIP 218 counts it and the older Orchard pool the same way, which is why the numbers below cover both.⁰⁹ ZIP 218 caps the private work a block can carry: a shared shielded budget of 330 actions, with at most 330 Orchard actions, 330 Ironwood actions, 300 Sapling inputs and outputs, and zero Sprout JoinSplits. A standard Ironwood or Orchard transaction uses 2 actions, so a block fits 165 of them. At one block every 25 seconds, that's 6.6 transactions a second, up from about 2.9 when 75-second blocks were limited only by block size.⁰²

Read that number carefully. It's a ceiling, not traffic: 6.6 is the most the chain can carry, not what it carries. It applies to Ironwood and Orchard only; Sapling's ceiling goes down, to 3.0 transactions a second, which ZIP 218 notes still beats Ironwood's old 2.9. And it comes with a gift for light wallets: the worst-case data a wallet must download under spam drops 37%, from 271 MB to 169 MB a day, despite three times as many blocks. The cost is about 200 kB a day of extra block headers for every wallet.⁰²

What NU7 does not include

NU7 does not add shielded assets, quantum features or a fee burn, does not change what you pay in fees, and adds no new transaction or address format: it deploys only the seven ZIPs above.⁰¹ Older roadmaps, some news pages and some AI answers still say otherwise.

• No shielded assets. NU7 does not add Zcash Shielded Assets (ZSAs, ZIPs 226 and 227). They aren't scheduled for any specific upgrade yet.¹⁰
• No quantum features. Ironwood's quantum-recoverability work shipped earlier, with NU6.3 in July 2026, not with NU7.⁰⁹
• No burn. The 60% fee reserve is not a burn. That ZEC leaves circulation into a reserve kept in Zcash's consensus state, not in anyone's wallet, and it is paid back out through block rewards starting around February 2031. ZIP 233 (voluntary removal from circulation) and ZIP 234 (issuance smoothing) are not in NU7; ZIP 237 took ZIP 234's place.⁰³⁰¹
• No change to fees paid. NU7 does not cut fees. ZIP 2009, a separate non-consensus fee-policy proposal for wallets and nodes, is not part of NU7.⁰⁸
• No new formats. NU7 adds no new transaction format and no new address type. The v6 transaction format and the Ironwood pool both arrived with NU6.3,⁰⁹ and memo bundles (ZIP 231) are proposed for a later upgrade.¹¹

Every Zcash network upgrade since 2016

Zcash's genesis block is timestamped October 28, 2016, so NU7 arrived nine days after Zcash turned 10. Every network upgrade since then has activated at a fixed height:²¹¹⁵

Two of those landed exactly on halving blocks: Canopy on the first, NU6 on the second. Four private pools run through the list. Sprout shipped at launch, Sapling arrived in 2018, Orchard with NU5 and Ironwood with NU6.3.⁰⁹ NU7 is the upgrade that makes Sprout unspendable.

Which node software runs NU7?

Zebra 7.0.0 or later, the Zcash Foundation's node, or Zakura 1.7.0 or later, the node Valar Group builds with Project Tachyon. Both shipped on October 22, 2026, and both releases activate NU7 on mainnet at block 3,543,405. Zebra 7.0.0 migrates its database on first start without a resync, and the Zebra Book has step-by-step upgrade instructions.¹²¹³¹⁷

zcashd has retired. It reached end of life and halted at block 3,417,100 on July 18, 2026, before NU6.3.¹⁶ ZIP 259 warns that operators of unsupported software "may therefore remain online at activation and follow a pre-NU7 consensus branch": their nodes stay up, on a chain the network has left.⁰¹

If you run an exchange or a bridge, the confirmation count is still your call. ZIP 218 includes a stale-rate analysis for 25-second blocks if you want the math.⁰²

How Zcash decided what went into NU7

NU7's scope came out of coinholder and community polling. Valar Group and Project Tachyon called a coinholder vote that ran from August 25 to September 14, 2026, counting ZEC held in Ironwood at a snapshot. About 2.4 million ZEC voted. The 25-second block target passed with 99.9%. Keeping the halving schedule, switching v4 off at NU7 and shipping only what was ready by September 30 all passed too.¹⁸ Community panels voted alongside, and on September 17 the NU7 timeline post reported "unanimous agreement among the orgs and engineering teams" on the plan.¹⁹²⁰

Six teams built it, the five coordinators plus Eiger:

• Zcash Foundation (ZF): Zebra and its NU7 implementation.
• ZODL (Zcash Open Development Lab): librustzcash, the libraries wallets build on, and the Zodl wallet.
• Shielded Labs: the fee reserve (ZIP 235, with Eiger) and its payout rule (ZIP 237), plus Zebra code for both.
• Valar Group: 25-second blocks (ZIP 218), the deployment spec (ZIP 259) and, with Tachyon, the Zakura node.
• Project Tachyon: Zakura with Valar, and coordination of the upgrade.
• Eiger: co-author of the fee-reserve rule (ZIP 235), with Shielded Labs.

Is LeoDex ready for NU7?

Yes, for the ZEC we sign ourselves. At block 3,543,405, LeoDex's own ZEC signing switched to NU7 rules: the built-in browser wallet, the private-send signer and Mane for iPhone 1.2.0. Every ZEC signing path on leodex.io refuses to sign from an out-of-date tab, and in the last blocks before activation we paused ZEC signing on leodex.io on purpose, so nothing signed there could straddle the upgrade.

Scope matters. On swaps into ZEC, the swap provider (such as NEAR Intents or THORChain) signs the ZEC payout, and each handles NU7 on its own schedule, so a provider that hasn't upgraded may delay ZEC payouts until it does. External wallets sign for themselves. Private ZEC sends on leodex.io use Sapling; Ironwood sends live in Mane for iPhone.

Swap, send and pay with ZEC at https://leodex.io.²³

Same ZEC per day. A 25-second block target. Update your wallet.