Zcash Tests Upgrade to Cut Block Times From 75 to 25 Seconds

TL;DR

• Zcash activated NU7 on its public testnet at block 4,465,026.

• The upgrade reduces targeted block intervals from 75 seconds to 25 seconds.

• Both Zakura and Zebra node software now support the testnet trial.

• NU7 changes transaction-fee allocation while preserving the existing ZEC issuance schedule.

Zcash has activated its NU7 upgrade on its public test network, beginning a trial of changes designed to make payments faster and adjust how the network supports future mining rewards.

The upgrade switched on at block 4,465,026. Zakura, node software that follows the Zcash blockchain and verifies transactions, now recognizes the new rules as active on the public testnet. An earlier, separate testing network has been shut down.

The public trial gives developers, exchanges, and other infrastructure operators an opportunity to check compatibility before the changes reach the live network. 

Testnet coins have no monetary value, allowing participants to evaluate the upgrade without using real ZEC.

November remains the target for mainnet deployment, but developers have not yet selected an activation block.

Shorter Block Intervals Could Speed Up Payments

NU7 reduces Zcash’s targeted interval between blocks from 75 seconds to 25 seconds. Each block contains a batch of transactions, so producing blocks more frequently could reduce the time users wait for payments to receive confirmations.

For example, a merchant or exchange requiring three confirmations would face a targeted wait of approximately 75 seconds rather than 225 seconds, provided it keeps that requirement unchanged.

Those figures are targets rather than guaranteed processing times. Actual block intervals vary, and services can set their own confirmation requirements.

The change therefore offers the potential for quicker payment acceptance and deposit crediting. The practical improvement will also depend on how businesses apply the upgraded network’s confirmation rules.

Both major Zcash node programs now support the public testnet upgrade. Zakura released its NU7 implementation on Oct. 1. The Zcash Foundation followed with a test version of Zebra on Oct. 2, giving operators another compatible implementation.

Node operators need software that recognizes NU7 to follow the upgraded test network correctly. The public testing period provides a shared environment for checking transaction processing and infrastructure behavior under the new rules.

Developers plan to review the results on Oct. 20 and decide whether to proceed with mainnet activation. Nov. 5 remains the proposed launch date, subject to that assessment.

Fee Changes Preserve the Issuance Schedule

Alongside faster blocks, NU7 changes the allocation of transaction fees. Miners will receive 40% of fees. The remaining 60% will be removed from circulation and recorded in a reserve intended to support future mining rewards as newly issued ZEC declines.

Mining rewards compensate participants for checking transactions and securing the network. The reserve mechanism is intended to contribute to those payments over time.

More frequent blocks will not mean three times as much new ZEC enters circulation. NU7 reduces the scheduled reward per block to one-third of its previous amount, preserving the existing issuance schedule despite the shorter block interval.

Sprout Users Face a Migration Requirement

NU7 also disables transactions associated with Sprout, Zcash’s oldest private-payment system.

Users holding funds in Sprout would need to move them before mainnet activation to retain the ability to spend those funds through the existing system. The planned retirement makes preparation relevant for affected holders, alongside the software updates required by infrastructure operators.

For now, all these changes are active on testnet. The Oct. 20 review will determine the next step toward bringing faster blocks, revised fees, and Sprout’s retirement to the live Zcash network.