Zcash has officially advanced to the next phase of its protocol evolution, activating its highly anticipated NU7 network upgrade on the testnet. This milestone moves the planned protocol changes into a live, operational testing environment roughly one month ahead of its targeted mainnet rollout.
According to data from the Zcash testnet block explorer ZecBlock, block 4,465,026—which marked the scheduled activation point for NU7—was successfully mined on Oct. 4 at 18:21:45 UTC. Shortly after the milestone was achieved, Zcash confirmed the successful activation in an official post on the social media platform X, declaring that NU7 was officially live on the testnet and ready for evaluation by developers, node operators, and the broader community.
NU7 represents the next major network upgrade for Zcash and introduces several structural modifications to the blockchain’s underlying architecture. Among its most prominent features, the upgrade seeks to drastically reduce the network’s target block spacing from the current 75 seconds down to just 25 seconds. By accelerating block times, the protocol aims to improve overall transaction throughput and user experience across the network.
In addition to faster blocks, the NU7 upgrade implements critical changes to transaction handling and ecosystem economics. Specifically, the upgrade permanently disables version 4 transactions. Furthermore, it integrates a newly designed Network Sustainability Mechanism, a feature engineered to redirect a designated portion of network transaction fees back into future block rewards, thereby supporting the long-term economic security and sustainability of the blockchain.
The disabling of version 4 transactions, however, carries significant implications for users holding funds in older, legacy infrastructure. Most notably, any ZEC held within Zcash’s legacy Sprout shielded pool will become entirely unspendable following the full activation of NU7 unless holders actively migrate their funds prior to the upgrade. This requirement has placed a strong emphasis on user preparedness and timely asset management ahead of the mainnet transition.
Ahead of the testnet activation, the Zcash Foundation issued a technical advisory on Friday, strongly encouraging testnet operators and community validators to deploy the release candidate to thoroughly test NU7 under real-world conditions. This crucial testnet phase provides developers and network participants with a vital window to assess the stability, performance, and security of the upgrade before making a final determination on whether to proceed with mainnet deployment.
Following the live testnet deployment, Zcash developers are scheduled to convene on Oct. 20 to review performance metrics, evaluate any potential issues encountered during testing, and make a final, formal decision on mainnet activation. During this meeting, the core development team will set the exact activation height for the mainnet rollout, which is currently targeted for Nov. 5.
The testnet activation of NU7 marks a critical turning point for the privacy-centric cryptocurrency as it prepares for one of its most substantial technical overhauls to date. As developers monitor the testnet environment over the coming weeks, attention will increasingly shift toward the upcoming Oct. 20 decision meeting and the preparations required for the anticipated November mainnet deployment.
