# Zcash Starts NU7 Testnet Trial With 25-Second Block Target

By Simon Yoon

Canonical URL: https://www.tokenpost.com/news/technology/26735
Published: 2026-10-05T04:45:47.000Z
Updated: 2026-10-05T04:45:47.000Z
Section: Technology

> The upgrade activated on the public testnet Oct. 4, two days before its scheduled milestone. Mainnet activation remains targeted for Nov. 5, subject to review.

Zcash began testing its NU7 upgrade on the public testnet Oct. 4, giving developers and node operators a chance to evaluate a change that targets 25-second blocks ahead of a conditional Nov. 5 mainnet activation target.

The upgrade activated at block 4,465,026. The testnet milestone had been scheduled for Oct. 6. NU7 changes Zcash’s target block spacing from 75 seconds to 25 seconds, although actual block times can vary. For services that wait for a fixed number of confirmations, the shorter target may reduce confirmation waits.

NU7 also introduces a Network Sustainability Mechanism. Under the planned rules, miners receive 40% of transaction fees, while the remaining 60% goes to a reserve for future block rewards. Per-block rewards are adjusted as part of the changes, with the stated aim of preserving Zcash’s issuance schedule.

The upgrade disables version 4 transactions used by Zcash’s legacy Sprout privacy system. The change may affect holders who still have funds in Sprout.

On Oct. 20, developers expect to assess the testnet results and choose a block height for mainnet activation. Nov. 5 remains the target activation date, subject to that review. NU7 has not activated on mainnet.