Zcash’s planned NU7 network upgrade would permanently close the protocol’s remaining on-chain route for spending funds held in its oldest privacy pool, Sprout, unless holders move those coins before activation. The upgrade is targeted for around Nov. 5 at block 3,543,405, and would disable the v4 transaction format required for Sprout transfers. About 22,263 ZEC remained in Sprout at publication, according to Zcash network data cited in the upgrade materials.
Those balances would remain counted as issued ZEC, but their owners could no longer move them through the Zcash protocol after NU7 activates. At a ZEC price near $1,300 cited in the supplied market data, the affected balance is worth roughly $30 million. The amount represents about 0.14% of circulating supply and approximately 0.45% of coins held in shielded pools.
The proposal to use block 3,543,405 as the activation height was made by Bowe on Oct. 20. Because Zcash block production can vary, the calendar date is an estimate rather than a fixed cutoff. Users with Sprout funds have a narrow window to recover their wallet data and complete a migration before the v4 format is retired.
Sprout holders face a one-way deadline
Sprout was Zcash’s original shielded pool, introduced with the network’s launch. It uses an earlier transaction design that depends on v4 transactions for spending. Newer Zcash transaction formats, including v5 and v6, do not support movements from Sprout.
ZIP 2003, the Zcash Improvement Proposal included in NU7, would prohibit all v4 transactions from the activation block onward. That rule removes the only protocol-level mechanism for spending a Sprout note. Since Sprout inflows were already closed under the 2020 Canopy upgrade, the pool has effectively been in a withdrawal-only phase for years.
The result is different from a conventional token burn. The affected ZEC would not be removed from Zcash’s 21 million supply cap, nor would the protocol transfer the coins to a new owner. They would remain recorded in the legacy pool while becoming unspendable on-chain under the updated consensus rules.
The deadline particularly affects users who have left older Zcash wallets inactive for years. Zallet, the newer wallet software, does not support importing Sprout spending keys or moving Sprout balances. Remaining users generally need older software, chiefly zcashd, along with the original wallet.dat file or the relevant Sprout spending key.
Recovery may become more difficult where historic wallet information is incomplete. Third-party software such as Argos can restore access using a wallet.dat file or an individual Sprout spending key in some cases, but successful spending also depends on note data and cached witnesses, the cryptographic information used to prove a shielded coin can be spent.
Users without that local data may need to conduct a full blockchain rescan. The supplied upgrade details estimate that process can require handling about 280 GB of blockchain data and may take days, leaving little room for holders who begin recovery close to the activation height.
Migration requires a public step
Even users who can access their Sprout coins cannot transfer them straight into Zcash’s later Sapling shielded pool. ZIP 308 requires funds leaving Sprout to pass through the transparent value pool before they can enter a newer shielded address.
That route creates a privacy trade-off for the oldest balances. The value leaving Sprout and passing through a transparent address becomes publicly visible on the blockchain, even though a user may later send the funds into a newer shielded pool. Holders whose funds are connected to sensitive transaction histories may need to consider the exposure created by that required intermediate step.
The migration design reflects Zcash’s long-running effort to retire its first-generation privacy system in favor of newer shielded technology. For ordinary users of Sapling, Orchard, or transparent ZEC, the v4 shutdown does not impose the same wallet-recovery deadline. Its direct effect falls on the small but persistent stock of coins still held in Sprout.
Faster blocks and a new fee reserve
NU7 also changes Zcash’s block cadence. Average block times would fall to 25 seconds from 75 seconds, tripling the expected frequency of blocks. The mining reward paid per block would be cut to one-third of its current level, preserving the network’s daily issuance rate.
That structure leaves Zcash’s 21 million maximum supply and its existing halving schedule unchanged. Miners would receive smaller individual rewards more frequently, rather than receiving more ZEC over a day. Shorter intervals could also reduce the expected confirmation wait for exchanges, payment services, and other businesses processing deposits.
The upgrade introduces a separate treatment for transaction fees. Under the proposed sustainability mechanism, miners would receive 40% of transaction fees in each block, while 60% would be removed from immediate circulation and placed into a reserve.
The reserved fees are scheduled to return gradually through future mining rewards beginning around February 2031, at mainnet block 8,939,664. This creates a delayed fee distribution model: some fees that would otherwise reach miners immediately would instead supplement rewards years later. The mechanism changes short-term fee flow without changing Zcash’s fixed issuance cap.
A September 2026 governance vote among coin holders showed broad support for the planned direction, according to the supplied vote figures. About 2.4 million ZEC participated, with 99.9% supporting 25-second blocks and the v4 transaction shutdown included in NU7.
Node operators need to follow the activation height
Network participants running Zcash infrastructure will need compatible node software before the consensus change activates. Nodes that do not recognize NU7’s rules could reject valid post-upgrade blocks or follow an obsolete chain, a routine but consequential operational risk during hard-fork upgrades.
The supplied materials also state that the final deployment code had not yet been merged into the main software repository. That leaves the activation plan dependent on the project’s remaining release process and makes the block height, rather than a calendar estimate, the more useful reference point for operators and legacy Sprout holders.
For the wider Zcash market, the amount stranded in Sprout is small relative to total supply. For individual owners, the outcome is absolute: once v4 support ends, possession of a legacy address or an incomplete wallet backup will no longer provide a route to spend the coins held there.
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