Zcash NU7 Upgrade Freezes $16M in Sprout Privacy Pool

The Zcash NU7 upgrade activates at block 3,543,405 on November 5, 2026. It makes remaining funds in the old Sprout privacy pool unspendable. Chain data shows about 12,224 ZEC still in Sprout, roughly $15 million to $16 million near recent ZEC prices around $1,230. Holders keep their keys. They lose the ability to move those notes once version-4 transactions are rejected.

The cut lands while altcoins watch privacy-coin headlines, including a separate Winklevoss Asset Services Zcash ETF filing track. Clock estimates put activation near 9:30 p.m. Eastern. The network rule fires at the height, not the clock.

How the Zcash NU7 Upgrade Locks Sprout Funds

Per ZIP 2003 and ZIP 259, NU7 disallows all version-4 transactions. Sprout transfers only exist in that format. Newer v5 and v6 formats do not carry Sprout spends. So leftover Sprout notes cannot move after activation.

The ban is network-wide. It is not a wallet setting users can opt out of. Private keys alone do not restore spending once consensus rejects v4. Sapling, Orchard, and transparent ZEC outside Sprout stay spendable under the supported formats.

ZIP 2003 does not burn or unissue the Sprout balance. The coins remain counted as issued supply. A later upgrade could theoretically restore a spend path. The ZIP also says that path may never return. Holders should treat remaining Sprout funds as practically locked once NU7 activates.

Faster Blocks and New Fee Rules Under NU7

NU7 also cuts the target block interval from 75 seconds to 25 seconds. Blocks arrive about three times faster. Three confirmations 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. Per-block subsidy falls because blocks come more often, while daily issuance stays broadly stable.

ZIP 235, deployed with NU7 per ZIP 259, routes 60% of transaction fees out of circulation into the Network Sustainability Mechanism. Miners keep the other 40%. Planned NSM reissuance sits near height 8,939,664, around 2031 on the mainnet schedule.

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 non-Sprout balances.