The Zcash team has shortened the intended pause between groups of transactions from 75 seconds to 25 on a public test network, and the update is now active sooner than expected. The adjustment, known as NU7, switches on at block 4,465,026, which gives trading platforms, wallets and builders a real-world trial run before the scheduled November mainnet deployment.
The Block Time Shrink
A single block documents a set of payments at once. Quicker creation lets sellers take payments sooner and exchanges credit deposits faster. A system that holds off until three confirmations arrives would face a shorter delay, although actual block times differ from one another. The testing network relies on coins with no real value attached, which gives developers and infrastructure operators a place to check the changes before they touch live ZEC.
What NU7 Changes
NU7 redirects 60% of transaction fees to a reserve for future mining rewards. Miners receive 40%, while the remaining 60% is removed from circulation and recorded in a reserve intended to fund those rewards. Those rewards pay miners to keep checking transactions as the amount of newly issued ZEC declines.
The creation of new coins would not triple even if blocks arrived faster. Instead, the reward paid out for each block simply drops to one-third of what it was, keeping the issuance schedule steady.
Sprout Transactions Are Disabled
The update also shuts off the transactions relied on by Sprout, Zcash’s longest-running private-payment method. People with money sitting in Sprout will have to shift their balances before mainnet launch if they want to keep spending those funds using the current system.
Test Network Activation
Zakura, a software that tracks Zcash and its transactions, now shows the upgraded rules as active on public testnet. The upgrade turned on at block 4,465,026, and the system’s earlier, distinct testing network has been shut down.
Mainnet Decision Timeline
The developers intend to examine the test outcomes and make a determination on mainnet activation by Oct. 20. Nov. 5 is still the goal date, though no mainnet activation block has been assigned yet.
| Feature | NU7 Test Network |
|---|---|
| Target block time | 25 seconds (down from 75) |
| Activation block | 4,465,026 |
| Fees | 40% to miners, 60% to reserve |
| Sprout transactions | Disabled |
| Mainnet decision | Oct. 20 |
The October Deadline
The date developers set aside for reviewing the test results and deciding whether to turn on mainnet is Oct. 20. That choice will be what determines whether Nov. 5 ends up being the actual launch date.
Before the upgrade, people who hold funds in Sprout need to move them if they want to keep using the old system to access their holdings.
What Developers Should Watch
The test network serves as a rehearsal, and that rehearsal is currently underway. Close monitoring of the test outcomes is advised for developers, with particular focus on how faster blocks influence transaction processing, fee distribution and general network performance.
The reward per block drops to one-third, yet the total supply growth remains on track since the block time change does nothing to alter the issuance formula. Keeping the issuance schedule steady was one of the upgrade’s design goals.
The Bottom Line
The NU7 upgrade for Zcash marks a real-world trial of a quicker blockchain, and it arrived early. Its 25-second block time offers developers a functioning example before the November mainnet launch. The update keeps the issuance schedule intact, Sprout funds must be moved, and the October deadline will determine if Nov. 5 stands.
The next month belongs to monitoring, review and decision-making.
Source material: “Zcash’s 25-second blocks go live on public testnet ahead of schedule,” CoinDesk.
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