Zcash NU7: 25-second blocks and a freeze on old ZEC in Sprout on November 5
The Zcash NU7 upgrade went live on testnet on October 4, and the target date for mainnet is November 5. Blocks will come out every 25 seconds instead of 75, part of the fees will be burned, and halvings will stay. But for owners of old wallets, something else matters more: after the upgrade, coins in the Sprout pool become unspendable. We explain what changes, who it affects and what to do before November 5.
When NU7 goes live
NU7 is the next Zcash network upgrade. Several organizations in the ecosystem are preparing it, and according to Zcash developer Sean Bowe, they reached "unanimous agreement" on what goes into the upgrade and when. Cointelegraph and crypto.news report the following schedule:
| Date | What happens |
|---|---|
| September 30 | feature set frozen |
| October 4 | activation on testnet (block 4,465,026, 18:21 UTC) |
| October 20 | final decision on the mainnet launch and block height, based on testnet results |
| November 5 | target date for mainnet activation |
The November 5 date isn't set in stone. If problems turn up on testnet, the deadline could be moved on October 20. Still, plan around November 5: the most practical question of this upgrade is tied to that date.
What happens to old ZEC in Sprout
Sprout is the very first shielded pool in Zcash. People used it in 2016–2017, before the network moved to newer formats. You haven't been able to deposit into Sprout for a long time, but the coins still sitting there can be spent. Right now the pool holds less than 23,000 ZEC.
Only version 4 transactions can spend ZEC from Sprout. The newer transaction formats don't support it. NU7 disables version 4 transactions the moment it activates, so after the upgrade the funds in Sprout become unspendable: technically the coins stay where they are, but there will be no way to move them out.
Who this affects
Check whether any of the following applies to you:
- a Zcash wallet created in 2016–2017, before 2018;
- addresses that start with zc;
- an old wallet.dat file from a Zcash full node.
If you bought ZEC recently and keep it in a modern wallet, NU7 will barely affect you. Sean Bowe says the upgrade "should not noticeably affect wallets" and introduces no new transaction formats. Sprout doesn't concern coins you got by swapping on VertEXchange either: they arrive at a transparent t1 or t3 address.
What to do before November 5
The general steps: open the old wallet in a Zcash full node, wait for it to sync, and move the funds from Sprout to a new shielded address in a modern wallet. This has to happen before NU7 activates on mainnet, that is, before November 5, 2026. Don't leave it to the last few days: syncing an old wallet can take a while. Once the coins are in the new wallet, you can keep holding them or, if you want privacy by default, swap ZEC for Monero with no account.
If you're not sure how to do it, or the wallet won't open, ask on the Zcash community forum. There is a dedicated thread there about recovering old wallets before the Sprout freeze.
Watch out for scammers
News of a "freeze" is a convenient excuse for fraud. Keep a few simple rules in mind:
- nobody does the "migration" for you, not support, not the developers, not "helpers" from chat groups;
- never send your seed phrase or wallet.dat file to anyone or upload them anywhere;
- only move coins to a wallet address you created yourself.
Whoever has the wallet.dat or the seed phrase has the coins. If it's been a while since you checked where your keys are, our guide on how to store a seed phrase so you never lose access to your wallet will come in handy.
Blocks every 25 seconds
The second noticeable change is block time. Right now a Zcash block comes out every 75 seconds; after NU7 it will be every 25 seconds. The change is described in ZIP 218, which is what Zcash calls its protocol improvement proposals.
For users, this means a transfer gets into a block faster and collects confirmations faster. Daily ZEC issuance stays the same: there will be three times as many blocks, and each block reward will be three times smaller.
| What we compare | Before NU7 | After NU7 |
|---|---|---|
| Block time | 75 seconds | 25 seconds |
| Block reward | current | three times smaller |
| Daily ZEC issuance | unchanged | unchanged |
| Halvings | yes | kept |
| Version 4 transactions | work | disabled |
Halvings and fee burning
Halvings in Zcash stay. Replacing them with smooth issuance was also on the table, but holders voted to keep the familiar model.
What's new is the Network Sustainability Mechanism (NSM). At least 60% of transaction fees will be taken out of circulation, meaning burned. Reissuance of these coins will start in February 2031.
How ZEC holders voted
The contents of NU7 were put to a coin holder vote. According to crypto.news, almost 2.4 million ZEC took part, about 66% of the balances eligible to vote.
| Question | Result |
|---|---|
| Keep halvings | for: 2,375,932 ZEC, 98.9% |
| NSM reissuance starting February 2031 | for: 2,319,644 ZEC, 96.6% |
| Faster blocks | for: 99.9% by ZEC weight |
| Disable version 4 transactions | approved |
The figure on faster blocks comes from Cointelegraph.
Who else will need to make changes
Ordinary users of modern wallets don't need to do anything. Full nodes, indexers and block explorers, on the other hand, may need updates, according to Sean Bowe. If you run your own Zcash node, keep an eye out for new software releases before November 5.
Zcash isn't the only one preparing a big upgrade. We've already covered what the Monero FCMP++ upgrade changes for transaction privacy.
What's going on with the ZEC price
Since September 1, ZEC climbed from about $860 to a peak of $1,687.78 on September 27, and by September 30 it had dropped to about $1,393, Decrypt reports. On October 1, clients of the Grayscale ZEC fund pulled out $30.25 million. The market cap of all privacy coins is now around $33.6 billion, compared with $7.1 billion a year ago.
How to buy Zcash before the upgrade
If you want to hold ZEC in a modern wallet, you can buy Zcash with Bitcoin without registration. The VertEXchange form only accepts transparent addresses starting with t1 or t3 for receiving ZEC. Get the coins to a transparent address, then shield them in your own wallet; the steps are in our guide on how to buy Zcash and move it to a shielded address.
FAQ
When is the Zcash NU7 upgrade coming out?
NU7 went live on testnet on October 4, 2026 at 18:21 UTC, at block 4,465,026. The target date for mainnet is November 5, 2026. The final decision on the launch and block height will be made on October 20, based on testnet results.
What happens to ZEC in the Sprout pool after NU7?
It becomes unspendable. Only version 4 transactions can spend coins from Sprout, and NU7 disables them on activation. Funds need to be moved out of Sprout before November 5, 2026.
How do I know if my ZEC is in Sprout?
Most likely it is if your wallet was created in 2016–2017, your addresses start with zc, or you still have a wallet.dat file from a Zcash full node. If in doubt, ask on the Zcash community forum.
How do I move old ZEC out of Sprout?
Open the old wallet in a Zcash full node and move the funds to a new shielded address in a modern wallet. Do it yourself: never send your seed phrase or wallet.dat to anyone, and don't trust anyone offering to "migrate" your coins for you.
Will Zcash issuance change because of 25-second blocks?
No. There will be three times as many blocks and each block reward will be three times smaller, so daily ZEC issuance stays the same. Halvings are kept.
What is NSM in Zcash?
The Network Sustainability Mechanism takes at least 60% of transaction fees out of circulation. Reissuance of these coins will start in February 2031.
Do owners of modern Zcash wallets need to do anything?
As a rule, no. According to Zcash developer Sean Bowe, the upgrade should not noticeably affect wallets and introduces no new transaction formats. Full nodes, indexers and block explorers may need updates.
Swap BTC for ZEC: the coins arrive at your transparent address, and you can shield them in your own wallet. No account needed.
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