Zcash has officially advanced its upcoming protocol evolution by activating the NU7 network upgrade on its testnet, transitioning months of theoretical development and community deliberation into live, real-world testing. This milestone brings the privacy-focused cryptocurrency roughly one month away from its anticipated mainnet deployment, giving developers, node operators, and the broader ecosystem a critical window to evaluate the software under operational conditions.
According to data from the Zcash testnet block explorer ZecBlock, block 4,465,026—which served as the predetermined activation point for NU7—was successfully mined on Oct. 4 at 18:21:45 UTC. The core development team and institutional bodies behind the project quickly confirmed the achievement, with Zcash taking to the social media platform X to formally announce that NU7 was live and operating on the testnet.
The activation marks a significant step forward for the protocol, introducing several architectural modifications designed to alter transaction processing speeds, economic models, and legacy system compatibility. At the core of the NU7 upgrade is a structural change to block times. The network currently targets a block spacing of 75 seconds, but NU7 aims to dramatically accelerate this metric, reducing the target block spacing down to 25 seconds. This threefold increase in block generation speed is intended to make the network more responsive for everyday users, improving transaction finality and overall throughput.
In addition to faster blocks, the upgrade introduces notable changes to transaction formatting and network economics. NU7 permanently disables version 4 transactions, phasing out older code structures to streamline the protocol and enhance long-term maintenance. Furthermore, the upgrade integrates a novel economic feature known as the Network Sustainability Mechanism. This mechanism is designed to redirect a designated portion of transaction fees back into future block rewards, altering how the network sustains its security and validator incentives over the long term.
However, the deprecation of version 4 transactions carries a critical operational warning for long-term holders. The disabling of these legacy transactions means that any ZEC cryptocurrency currently held within Zcash’s older Sprout shielded pool will become entirely unspendable once NU7 activates fully on the mainnet. To prevent permanent loss of access to these assets, affected users are strongly advised to move their funds out of the legacy Sprout pool and into modern shielded pools before the upgrade takes full effect.
Ahead of the testnet activation, the Zcash Foundation released a statement noting that testnet operators and node runners should immediately begin utilizing the release candidate to test NU7 under genuine network conditions. This testing phase is considered an essential safety measure, providing developers with the necessary empirical data to assess the upgrade’s stability, security, and performance before deciding whether to proceed with a mainnet release.
The timeline moving forward leaves a tight schedule for final validation. Zcash developers are scheduled to convene on Oct. 20 to review the performance of NU7 on the testnet, at which point they will make a final, formal decision regarding mainnet activation and establish the exact activation block height. If the testnet phase proceeds without encountering critical bugs or unforeseen complications, the mainnet activation of NU7 is currently targeted for Nov. 5, ushering in one of the most substantial structural updates to the Zcash network in recent history.
