Zcash has officially activated its highly anticipated NU7 network upgrade on the testnet, marking a major milestone that transitions the protocol’s planned changes into a live testing environment approximately one month ahead of its targeted mainnet rollout.
According to data from the Zcash testnet block explorer ZecBlock, block 4,465,026—which served as the scheduled activation point for the NU7 upgrade—was successfully mined on Oct. 4 at 18:21:45 UTC. Shortly after the milestone block was processed, Zcash confirmed the successful deployment in an official post on the social media platform X, assuring the broader cryptocurrency community that NU7 was officially live and operational on the testnet.
The rollout of NU7 represents the next major network upgrade for the privacy-focused cryptocurrency project. The upgrade is designed to introduce several foundational changes to the Zcash protocol, most notably a drastic reduction in the network’s target block spacing. Under the current parameters, Zcash blocks are targeted at 75 seconds. The NU7 upgrade seeks to slash this duration down to 25 seconds, a move that would significantly speed up transaction confirmation times and improve overall network throughput for users.
In addition to faster block times, the NU7 upgrade includes critical protocol modifications, such as the complete disabling of version 4 transactions. This particular change also integrates a novel Network Sustainability Mechanism, which is designed to redirect a portion of transaction fees into future block rewards, altering the long-term economic model and token emission dynamics of the Zcash ecosystem.
However, the disabling of version 4 transactions carries significant implications for holders of the privacy coin. Specifically, the technical change means that any ZEC tokens currently held within Zcash’s legacy Sprout shielded pool will become entirely unspendable unless users actively migrate their funds to newer shielded pools before the NU7 upgrade fully activates on the mainnet. This operational requirement has prompted developers and community advocates to urge affected token holders to take immediate action to secure their assets.
Ahead of the testnet activation, the Zcash Foundation issued a statement on Friday encouraging testnet operators, node runners, and developers to utilize the newly released candidate to test NU7 under real-world operational conditions. This critical testing phase allows developers to thoroughly assess the performance, stability, and security of the upgrade before committing to a final decision regarding mainnet activation.
Zcash core developers are scheduled to meet and make a final determination on the mainnet activation on Oct. 20. During this decision-making process, developers will evaluate the empirical data and network behavior observed during the NU7 testnet phase to set the precise mainnet activation height. Subject to a successful evaluation period, the official mainnet activation for the NU7 upgrade is currently targeted for Nov. 5.
