Somewhere inside Zcash’s oldest privacy system, more than 12,000 ZEC are running out of time.
Their owners might still have the private keys. The blockchain still recognizes the coins. Yet within hours, those keys could become useless for moving them.
That’s the uncomfortable twist behind Zcash’s upcoming NU7 upgrade, which promises transactions three times faster while preparing to shut down the network’s original shielded pool.
According to the Zcash Foundation’s October 22 announcement, NU7 activates at block 3,543,405, expected around November 6 UTC. The upgrade reduces target block times from 75 seconds to 25 seconds without increasing ZEC’s daily issuance.
But speed isn’t the only factor.
More Than 10,000 ZEC Have Already Left
The network’s original privacy pool, Sprout, held 22,263.34 ZEC on October 30. By November 5, that balance had fallen to just 12,225.69 ZEC.
That’s a reduction of 10,037.65 ZEC, or 45.1%, in less than a week.
The comparison uses historical pool balances recorded by ZecStats and the latest figures from the Zcash on-chain dashboard, which reported a Sprout balance of 12,225.68627841 ZEC at block 3,542,331.
At the dashboard’s quoted ZEC price of $1,316.57, the remaining coins were worth roughly $16.1 million.
The sharp decline suggests substantial funds have already exited the aging privacy system ahead of its shutdown. However, aggregate pool balances cannot reveal who moved the coins, where individual funds ultimately went, or how many owners remain.
And those remaining owners face a deadline determined by code, not a calendar.
When Private Keys Stop Being Enough
The mechanism is straightforward, even if its consequences aren’t.
Under ZIP 2003, NU7 disables version 4 transactions. Sprout transfers depend entirely on that older transaction format, meaning coins still inside the pool become unspendable once the upgrade activates.
The coins won’t be burned. They won’t disappear from Zcash’s accounting either.
Instead, they could remain stranded indefinitely.
The proposal explicitly leaves open the possibility of restoring access through future protocol changes. But it also warns that spending might never be re-enabled.
For modern Zcash users outside Sprout, the transition is considerably less dramatic. NU7 also introduces a mechanism that temporarily removes 60% of transaction fees from circulation for future mining rewards while preserving the network’s 21 million ZEC supply limit.
The live NU7 tracker projected activation around 02:40 UTC on November 6, although the exact timing depends on when the chain reaches the designated block.
For Zcash, the upgrade represents a meaningful step toward faster private payments.
For anyone still holding coins in Sprout, it raises a rather different question.
What good is owning the keys when the network no longer accepts the transaction needed to use them?
