Zcash Activates NU7 Network Upgrade on Testnet Ahead of Planned November Mainnet Rollout

Zcash has officially activated its major NU7 network upgrade on the testnet, marking a critical operational milestone that transitions the protocol’s planned changes into a live testing environment approximately one month ahead of its targeted mainnet deployment.

According to data from the Zcash testnet block explorer ZecBlock, block 4,465,026—which served as the predetermined activation point for the NU7 upgrade—was successfully mined on Oct. 4 at 18:21:45 UTC. The Zcash development team quickly confirmed the successful activation shortly after via a public post on the social media platform X, assuring the broader cryptocurrency community that NU7 is now fully operational and live on the testnet.

The NU7 upgrade represents the next major network evolution for Zcash, introducing several profound technical modifications aimed at altering the foundational mechanics of the blockchain. Among the most prominent changes introduced in the NU7 upgrade is a dramatic reduction in the network’s target block spacing. While previous iterations of Zcash maintained a target block time of 75 seconds, the NU7 upgrade cuts this down significantly to just 25 seconds. By accelerating block times, the network aims to provide faster transaction confirmations and an improved user experience across the board.

In addition to faster block spacing, the NU7 upgrade introduces vital structural adjustments to transaction processing and network economics. The protocol update officially disables version 4 transactions, phasing out legacy structures in favor of more modern cryptographic frameworks. Furthermore, NU7 integrates a newly designed Network Sustainability Mechanism. This mechanism is intended to intelligently redirect a portion of network transaction fees directly into future block rewards, ensuring long-term economic stability and security for the miners and operators who maintain the underlying blockchain infrastructure.

However, the deprecation of version 4 transactions carries immediate practical implications for certain long-term holders. The disabling of these legacy transactions means that any Zcash (ZEC) tokens still held within the network’s legacy Sprout shielded pool will become entirely unspendable unless users actively relocate those funds before the NU7 upgrade fully activates on the mainnet. This transition phase serves as a vital reminder for participants holding assets in older shielded pools to audit their holdings and execute necessary transfers to modern addresses.

In light of these developments, the Zcash Foundation released a statement emphasizing the importance of the ongoing testnet phase. The organization noted that testnet operators and node runners should utilize the newly released software candidate to thoroughly evaluate and test NU7 under real-world operational conditions. This testing period provides developers, validators, and infrastructure providers with a crucial window to closely monitor the stability, performance, and security of the network before committing to a permanent mainnet activation.

The insights gathered from this live testnet environment will directly inform the final governance and technical decisions made by the core development team. Zcash developers are officially scheduled to convene and make a definitive final decision regarding the mainnet activation on Oct. 20. During this evaluation, the team will review the telemetry and performance data gathered from the NU7 testnet run and formally set the exact block height for the mainnet rollout.

If the current testing trajectory proceeds without encountering major technical roadblocks, the mainnet activation for the NU7 upgrade is targeted to take place on Nov. 5. As the crypto industry watches closely, the successful testnet deployment marks the beginning of the final countdown for one of Zcash’s most substantial architectural transitions to date.