Zcash (ZEC) NU7 Upgrade Cuts Block Time to 25 Seconds on November 5

NU7 Cuts Block Time to 25 Seconds

Zcash (ZEC) ships its NU7 network upgrade this week, a hard fork that cuts the target block time on the Zcash network from 75 seconds to 25 seconds. Activation is set for block height 3,543,405, which the deployment schedule places on November 5. The Zcash price has weakened into the change, sitting near $1,135 after an 11% decline, but the code reaching mainnet is substantial by this project's standards. Traders are weighing the network improvements against a live dispute over how the project funds development. Under ZIP 218, the protocol stops targeting a block every 75 seconds and instead aims for one every 25 seconds. For anyone waiting on confirmations, three blocks will clear in about 75 seconds instead of nearly four minutes, a difference that matters for the point-of-sale and private payment flows Zcash is built for. The upgrade also introduces limits on shielded transaction activity, framed in the release material as a way to improve network efficiency and protect wallets against spam. Shielded transactions hide the sender, recipient and amount, so those limits are being tuned to keep the privacy feature usable under load. A second change inside the same activation, ZIP 235, redirects 60% of transaction fees out of circulation and into a reserve. The mechanism is meant to backstop mining rewards as block subsidies shrink over time, giving miners a revenue stream sourced from actual network usage rather than new coins. Monetary policy itself is untouched: the existing 21 million ZEC supply cap and the four-year halving schedule both carry over unchanged, and the supply ceiling stays exactly where it has been since launch. What changes at block 3,543,405 is the cadence of the chain: blocks arrive three times as often, confirmations land faster, and a fee-funded reserve begins accruing for the first time.

Update (3 Nov 20:29 UTC): The Zcash Foundation's engineering update, published Nov. 3, details seven security fixes in Zebra 7.0.0, released Oct. 22 with NU7 support: five classified as high severity, including two checkpoint synchronization failures, and two as medium.

Sprout Deadline and the Grants Fight

Two operational items land alongside the faster blocks. NU7 disables version 4 transactions, the mechanism required to spend funds in the legacy Sprout pool. Sprout is Zcash's first shielded pool, and its parameters date back to the original Zcash ceremony, the trusted setup that generated the keys securing shielded transactions. Any balance left in Sprout past activation risks becoming unspendable, so holders should move coins to a new wallet address in an up-to-date crypto wallet before block 3,543,405. Node operators face the same deadline from the other side: consensus rules change at the activation block, and unupgraded software drops off the network's chain. The Zcash Foundation's Zebra 7.0.0 client ships with NU7 support on mainnet, plus additional synchronization and security fixes. The politics around the release are louder than the code. Co-founder Sean Bowe has put forward a proposal to stop the automatic 8% allocation of newly issued ZEC that flows to the Zcash Community Grants program. His post argues the treasury already carries roughly $125 million once existing commitments are counted, enough to fund years of development with no further automatic inflows. Under the proposal, that 8% would be steered toward the reserve ZIP 235 creates, while the committee keeps its current funds and keeps distributing grants. The dispute sharpened after scrutiny of a grant funding privacy-payment outreach at adult-industry events. Critics questioned the spending; supporters argued the program introduces privacy technology to users who face financial restrictions. Bowe's proposal does not mention that controversy and addresses treasury size and long-term sustainability instead. ZEC has sold off into the activation, dropping more than 10% in a single day, and futures positioning data showed longs absorbing $12.96 million in liquidations during the cascade. The Big Z exit over the grant dispute landed during the sell-off, and another whale stacked a $14 million position ahead of the NU7 hard fork.

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Our read is that the market is trading the governance argument, not the code. The engineering case for NU7 rests on fixed numbers: 25-second blocks, confirmations near 75 seconds and a 60% fee redirect. The price action has tracked the grants fight and the Big Z fallout instead. If the activation clears on Thursday without incident, the debate moves from whether NU7 should ship to whether the faster chain actually pulls in payment volume, and the levels on our Zcash technical analysis page are where that argument settles. What is not in dispute is what runs on Thursday that does not run today: 25-second block production, confirmation times around 75 seconds, and a fee reserve accruing on mainnet for the first time.

The Zcash Foundation's engineering update, published Nov. 3, details seven security fixes in Zebra 7.0.0, released Oct. 22 with NU7 support: five classified as high severity, including two checkpoint synchronization failures, and two as medium. One high-severity flaw let an unauthenticated peer supply a forged block body that stalled a syncing node until restart, though no invalid block reached disk and funds were unaffected. Installation moves the stored state from format v28 to v29, and Zebra 6.x cannot read the new format, so a rollback means full resynchronization. Operators must upgrade before block 3,543,405 to stay on the consensus chain. Separately, miner complaints at Zcon7 in Cancún about slow template creation produced Zebra Ándale (7.1.0-alpha.0), which cut a transaction burst that previously took over eight minutes to reach a mining template to roughly four seconds, per developer benchmarks.