Zcash NU7 Block 3,543,405: What It Means for Sprout Funds
Decrypt says regular Zcash holders using modern, supported wallets do not need to migrate their coins out of Sprout, although keeping wallet software updated remains important (Decrypt). The exception is ZEC still in the old Sprout pool: under ZIP 259, funds left there become unspendable at activation height 3,543,405, and Blockchair shows the chain past that height.
This guide was last updated on 2026-11-06. At 02:51 UTC, Blockchair showed block 3,543,426, past activation height. A second explorer still showed an older height, so it appears to be behind. We found no official activation announcement and no report of a split or halt, and we have not independently verified the rules now in force. Compare explorers and check official channels. BOTLAB is not affiliated with Zcash, the Zcash Foundation or any company named here.
What the sources say
- Activation height: NU7 activates on Mainnet at block 3,543,405, according to ZIP 259 and the Zcash Foundation.
- Sprout: after activation, funds remaining in the Sprout pool become unspendable, because version 4 is the only transaction format that can spend them, according to the Zcash Foundation.
- Not burned, but no promise of return: ZIP 2003 says the coins are not unissued or burned, but warns that the ability to spend them "may never be re-enabled."
- All version 4 transactions: this is wider than Sprout. ZIP 259 says the ban also covers transparent-only and Sapling version 4 transactions. Version 5 and version 6 transactions stay valid.
- Amount: Decrypt, citing ZecStats, reports about 12,224 ZEC left in Sprout, and notes nobody knows how much of it belongs to people who have lost their keys. We have not checked this figure ourselves.
Both ZIPs were marked "Proposed" in the copies we read.
Is your ZEC in Sprout?
On an exchange or with a custodian: the company controls the wallet, so check its official announcements or contact support from inside your account. The sources we read do not cover individual exchanges.
In your own wallet: Decrypt reports that Sprout addresses begin with "zc". We did not find that wording in the official documents we read, so confirm it in your wallet's documentation. Old wallets can hold several address types, so check all of them.
Shielded balances are private by design, so a block explorer generally cannot show you a Sprout balance. Your wallet has to read it using your own keys.
What to do now if you hold Sprout funds
- Check the current height on more than one public explorer and compare it with 3,543,405.
- Keep your wallet files, backups and seed phrase private and intact. ZIP 2003 says the coins are not burned, and that a future change could theoretically re-enable version 4, but it does not promise this.
- Follow only official Zcash channels for any later news.
- If you saved or offline-signed version 4 transactions, they will not work after activation. ZIP 259 says re-signing alone cannot make one valid. Transparent-only and Sapling transfers need to be rebuilt in a supported format, but Sprout transactions have no supported replacement format after activation.
If you run a node or a service
The Zcash Foundation says all Mainnet node operators must upgrade before NU7 activates to stay on the consensus chain. ZIP 259 says wallets and transaction services need to stop constructing version 4 transactions. Check the official release notes for the version you need.
Scams to watch for
Upgrades and deadlines attract scammers, because worried holders act quickly. Nobody legitimate will ask for your seed phrase or charge a fee to unlock or recover funds.
Warning signs include:
- Someone asks for your seed phrase, private keys or wallet backup file.
- A "recovery specialist" contacts you first, or offers to unlock frozen Sprout coins for a fee.
- A message links to a "migration" tool you did not find through official channels.
- A wallet update is offered through a reply, a direct message or a search ad.
Never type your seed phrase into a website.
FAQ
Do I need to do anything because of NU7?
Decrypt says regular holders using modern, supported wallets do not need to migrate their coins out of Sprout, although keeping wallet software updated remains important. It matters if your coins are in the Sprout pool, or if you rely on software that builds version 4 transactions.
Are Sprout coins gone forever after NU7?
They are unspendable, not burned, according to ZIP 2003. The same document says spending may never be re-enabled, so nobody can promise a way back.
Can someone recover frozen Sprout coins for me?
Treat any such offer as a scam. The sources we read describe no recovery service.
Can a block explorer show my Sprout balance?
Generally not, because shielded balances are private. Use your own wallet.
Key takeaways
- ZIP 259 sets NU7's Mainnet activation height at block 3,543,405, and Blockchair shows the chain past it. A second explorer was behind, so check the status yourself.
- ZIP 259 says funds left in Sprout become unspendable, and ZIP 2003 says spending may never be re-enabled.
- ZIP 259 says the ban covers all version 4 transactions, not only Sprout ones.
- Decrypt says regular holders on modern, supported wallets do not need to migrate, and that keeping wallets updated remains important.
- Never share your seed phrase, and never pay anyone to unlock funds.
General information, not financial advice. Crypto trading can lose money, including all capital. Check the official docs before you move funds.
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