Zcash to freeze $16M in its oldest privacy pool with NU7 upgrade

Electric Coin Company / Wikimedia Commons (Public domain)

The NU7 network upgrade will disable the transaction type needed to spend from Sprout, leaving roughly 12,226 ZEC stranded unless holders migrate first

Thu 5 Nov 2026 · 00:54 EST · 3 min read

In Altcoins

Zcash is about to retire its oldest privacy pool. When it does, about $16 million in ZEC still sitting there will become unspendable.

The cutoff arrives with the NU7 network upgrade, scheduled to activate around November 5–6, 2026, at block height 3,543,405. Anyone with coins left in the Sprout pool after that block will still own them. They just won’t be able to move them.

What NU7 actually changes

NU7 disables version 4 transactions. The catch is that version 4 transactions are the only way to reach the Sprout shielded pool. A shielded pool is a section of the Zcash ledger where transaction details are kept private. Sprout was the first one, launched back in 2016.

Sprout currently holds approximately 12,226 ZEC. With ZEC recently averaging $1,300 to $1,320, that stash comes to around $16 million.

The coins are not burned, and nobody is confiscating private keys. The ZEC stays counted in the total supply. But once NU7 is live, any attempt to transact with Sprout funds will fail. There is currently no mechanism to recover them afterward.

The migration is already underway

Holders appear to be getting the message. The Sprout pool held roughly 22,300 ZEC in mid-October. It now sits at approximately 12,226 ZEC, a drop of a little under half in a short stretch.

The fix for holders is simple on paper: move Sprout funds into a supported wallet before activation. After the upgrade, that option disappears.

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Only version 4 transactions are affected. The newer Sapling, Orchard, and Ironwood pools will keep running normally and won’t be touched by NU7.

Why Sprout is being shut down

Sprout has been on borrowed time for a while. For several years, the pool has been limited to withdrawals only, meaning funds could leave but not come in.

Zcash has steadily layered newer privacy pools on top of the original design. Sapling, Orchard, and Ironwood each arrived later as part of the network’s ongoing modernization. NU7 continues that pattern of upgrades focused on modernizing the protocol and tightening security.

What this means for ZEC holders and the network

For anyone still holding Sprout funds, this is a straightforward deadline. Migrate before block 3,543,405, or accept that those coins will likely sit frozen indefinitely.

The people most at risk are probably not active traders. They are early users who shielded coins years ago and haven’t revisited their wallets since.

The balance drop since mid-October shows outreach is working, but approximately 12,226 ZEC remains unmoved.

On the market side, the stranded coins technically stay in total supply. In practical terms, though, anything left in Sprout after activation becomes coins that can’t circulate. If a large share stays put, that could create a temporary liquidity squeeze, which in turn may affect investor sentiment.

What to watch: the Sprout balance as November approaches, whether wallet providers make migration easier for holders, and whether any recovery mechanism is proposed down the line. As it stands, none exists, and the clock is running on block 3,543,405.

Disclosure: This article was edited by Estefano Gomez. For more information on how we create and review content, see our Editorial Policy.