Zcash NU7 Upgrade Freezes Roughly $16M in Sprout Privacy Pool
Key Takeaways
- •Zcash's NU7 upgrade activated at block height 3,543,405 on November 5, 2026, rendering the remaining funds in the original Sprout privacy pool unspendable.
- •Roughly 12,224 ZEC, worth about $15–16 million at recent prices near $1,230, are locked because NU7 disallows version-4 transactions, the only format the Sprout pool supports.
- •The spending ban is enforced at the consensus level rather than as an opt-out wallet setting, so private keys alone cannot move Sprout notes, while Sapling, Orchard, and transparent balances stay spendable.
- •The coins are not burned and remain counted as issued supply, and a future consensus change could theoretically reopen a spend path, though one may never return.
- •NU7 also cuts the block interval from 75 to 25 seconds, reduces three-confirmation times from about 3.75 minutes to roughly 75 seconds, keeps the 21 million supply cap and halving schedule intact, and sends 60% of transaction fees to the Network Sustainability Mechanism with miners receiving the other 40% and reissuance planned near height 8,939,664 around 2031.
The Zcash network's NU7 upgrade activated at block height 3,543,405 on November 5, 2026, rendering the remaining funds in the protocol's original Sprout privacy pool unspendable. Chain data shows roughly 12,224 ZEC still sitting in Sprout — approximately $15 million to $16 million at recent ZEC prices near $1,230. Holders retain their private keys, but they lose the ability to move those notes once version-4 transactions are rejected by consensus.
The cutoff lands as privacy-coin headlines draw attention across the altcoin market, including a separate Winklevoss Asset Services Zcash ETF filing track. Clock-based estimates placed activation around 9:30 p.m. Eastern, though the network rule triggers at the designated block height rather than at a fixed time.
How NU7 Locks the Sprout Pool
Per ZIP 2003 and ZIP 259, NU7 disallows all version-4 transactions. Sprout, the shielded pool the network launched with, has transfers only in that format, while the newer v5 and v6 transaction formats do not carry Sprout spends. As a result, leftover Sprout notes cannot move after activation.
The ban is enforced network-wide at the consensus level. It is not a wallet setting that users can opt out of, and private keys alone do not restore spending once v4 transactions are rejected. Sapling and Orchard — the newer shielded pools that succeeded Sprout — plus transparent ZEC held outside Sprout remain spendable under the supported formats.
ZIP 2003 does not burn or unissue the Sprout balance. The coins remain counted as issued supply, and a later upgrade could theoretically restore a spend path — though the ZIP itself notes that path may never return. Holders should treat remaining Sprout funds as practically locked once NU7 is active.
Faster Blocks and New Fee Rules Under NU7
NU7 also cuts the target block interval from 75 seconds to 25 seconds, meaning blocks arrive about three times faster. Three confirmations now drop from roughly 3.75 minutes to about 75 seconds.
The 21 million ZEC supply cap and the four-year halving schedule stay in place. Because blocks arrive more frequently, the per-block subsidy falls while daily issuance remains broadly stable.
In addition, ZIP 235 — deployed alongside NU7 per ZIP 259 — routes 60% of transaction fees out of circulation into the Network Sustainability Mechanism (NSM), with miners keeping the remaining 40%. Planned NSM reissuance is set near height 8,939,664, around 2031 on the mainnet schedule, when fees collected into the mechanism are scheduled to return to circulation.
The headline stake remains the Sprout pool: about 12,224 ZEC becomes unspendable at activation unless a future consensus change reopens a path. Everyone else keeps normal access to their non-Sprout balances.
