Zcash NU7 Moves Sprout Funds and Cuts Blocks to 25s
Short answer: Zcash’s NU7 network upgrade shortens block spacing from 75 to 25 seconds, sends at least 60% of transaction fees into a reserve, and disables version 4 transactions, which ends spending from the old Sprout pool. Mainnet is targeted for November 5, 2026, but the official upgrade page still said the activation height was not set. If you hold Sprout coins, moving them is the one action worth planning.
Most upgrade coverage is about speed. This one has a deadline buried in it.
Below: what changes, who has to act, and the open questions I could not close from public sources.
Educational content, not investment advice. Several NU7 specifications, including ZIP 218, were still listed as drafts in the sources I read, so details may change before activation.
Contents
- What changes in Zcash NU7?
- What happens to Sprout funds after NU7?
- Who needs to upgrade software?
- When does NU7 activate on mainnet?
- Are 25-second blocks risky?
- Loose Ends Worth Watching
What changes in Zcash NU7?
Zcash NU7 cuts the target block spacing from 75 seconds to 25 seconds, keeps daily ZEC issuance unchanged by reducing the subsidy per block, and routes at least 60% of transaction fees out of circulation, according to crypto.news’s September 18, 2026 report on the agreed scope.
| Item | Before NU7 | With NU7 (as proposed) |
|---|---|---|
| Target block spacing | 75 seconds | 25 seconds (ZIP 218, draft) |
| Daily issuance | unchanged | unchanged; subsidy per block reduced |
| Orchard throughput (2-action txs) | about 2.9 per second | about 6.6 per second |
| Transaction fees | to miners | at least 60% removed, up to 40% to miners (ZIP 235) |
| Version 4 transactions | allowed | disabled at activation (ZIP 2003) |
| Halvings | kept | kept; removed supply reissued from February 2031 |
When I compared two separate reports of the same plan, I found that they agree on the headline numbers. Coin holders backed keeping halvings with about 98.9% support and the faster blocks with 99.9% of the ZEC-weighted vote.
What happens to Sprout funds after NU7?
Zcash coins still sitting in the legacy Sprout shielded pool can no longer be spent after NU7 activates, because ZIP 2003 disables version 4 transactions, although the balances are not burned and stay on the ledger.
The scale is small. Sprout held under 23,000 ZEC and under 0.1% of transaction volume at the time of the vote, per crypto.news. Small is not zero, though, and old wallets are exactly where forgotten coins live.
If you suspect you have Sprout coins, check your wallet for a Sprout balance and move it to a shielded address you control before activation. Try a small amount first. This is general caution, not a wallet-specific instruction, so follow your wallet’s own migration guidance.
Who needs to upgrade software?
Full nodes, indexers and block explorers may need adjustments for NU7, while ordinary wallets are not expected to change much, according to Zcash developer Sean Bowe as reported on September 18, 2026.
The official NU7 page adds a detail that matters if you run your own node: if NU7 brings the expected consensus changes, zcashd will not support it, and users are told to move to the Zcash Foundation’s Zebra node. ASIC miners reportedly need no action and depend on their pool.
When does NU7 activate on mainnet?
Developers targeted November 5, 2026 for NU7 mainnet activation, with a go or no-go decision and the activation block height due on October 20, 2026 after about two weeks of testnet observation.
| Date (2026) | Milestone |
|---|---|
| September 30 | Feature-completion cutoff |
| October 4-6 | Testnet activation (block 4,465,026 on October 4, earlier than the October 6 estimate) |
| October 20 | Planned mainnet height decision |
| November 5 | Target mainnet activation |
I noticed that none of the sources I could open reported the outcome of the October 20 decision. The Zcash upgrade page I read still said no height had been set. Check the official page before relying on the November 5 date.
Are 25-second blocks risky?
Faster Zcash blocks raise the share of competing blocks, with a theoretical stale-block rate of about 3.26% at 25-second spacing and a 4.86% stale rate in a 99-node devnet test with 2 MB blocks, per crypto.news’s September 2026 summary.
That devnet figure was higher than the theory. It is a lab number. Mainnet behavior will tell the real story.
Loose Ends Worth Watching
You will probably notice the gaps by the end: no mainnet height in the sources, specs still labeled draft, and no exchange guidance. Exchanges usually pause deposits and withdrawals around upgrades, but I found no NU7 notice, so I will not guess at one.
Tips
- Check the official NU7 page for the activation height before planning anything.
- Move any old Sprout balance with a small test transfer first.
- If you run a node, read the Zebra migration notes now rather than the week of activation.
Warnings
- Never enter your seed phrase on a site offering to migrate your coins.
- Dates here come from reports that predate the October 20 decision.
- This is not investment advice.
FAQ
When does Zcash NU7 activate on mainnet?
Developers targeted November 5, 2026, contingent on an October 20 decision that sets the activation height. The official NU7 page I read still said the height had not been set.
Will I lose my Sprout ZEC after NU7?
Sprout funds are not burned, but ZIP 2003 disables version 4 transactions at activation, which stops further spending from Sprout. Moving the balance to a shielded address beforehand avoids the issue.
Does NU7 change the total supply of ZEC?
Daily issuance stays the same because the subsidy per block is reduced as blocks get faster, and halvings are kept, according to crypto.news. Removed fee revenue is meant to be reissued from February 2031.
Sources
- crypto.news: Zcash targets Nov. 5 for NU7 mainnet upgrade (September 18, 2026)
- Zcash: NU7 upgrade page
- Zcash official site
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Fact-checked against crypto.news and the official Zcash NU7 page. Not investment advice.
