SKN | Zcash Activates NU7 Upgrade, Tripling Block Speed and Strengthening Private Payment Infrastructure

Key Points:

• Zcash activated its NU7 network upgrade at block 3,543,405 on November 6, reducing the target interval between blocks from 75 seconds to 25 seconds.
• The upgrade limits private transaction activity per block, reducing the estimated worst-case daily wallet download burden from 271 megabytes to 169 megabytes while potentially more than doubling simple private-payment capacity.
• NU7 redirects 60% of transaction fees into a reserve for future mining rewards beginning around February 2031, while retiring the original Sprout privacy pool.

Zcash has activated its long-awaited NU7 network upgrade, introducing significant changes to transaction speed, wallet efficiency and the long-term economics of network security. The November 6 activation reduces the target time between blocks from 75 seconds to 25 seconds, potentially making shielded payments more practical for merchants, exchanges and cross-border transfers. Beyond transaction processing, the upgrade introduces a mechanism designed to supplement future mining rewards as the network’s scheduled issuance declines.

Shorter Block Intervals Could Improve Payment Usability

The NU7 upgrade went live at block 3,543,405, mined at approximately 02:34 UTC on Friday, according to network data cited by CoinDesk. By 04:59 UTC, the network had produced another 225 blocks, averaging approximately 39 seconds apart as mining difficulty continued adjusting toward the new target.

The reduction could materially shorten confirmation waiting times. A merchant receiving a payment could see its first confirmation in approximately 25 seconds on average, while an exchange requiring three confirmations could reduce its expected waiting period from nearly four minutes to approximately 75 seconds. Actual processing times will vary, however, because individual services determine their own confirmation requirements.

For Zcash, which allows users to conceal transaction senders, recipients and amounts, faster confirmation times could improve the practicality of private digital payments. The development is particularly relevant to payment services that need to balance transaction privacy with operational efficiency.

Wallet Efficiency Becomes a Central Technical Priority

Faster block production creates additional technical demands because miners have less time to receive and validate competing blocks. If blocks arrive before information about previous blocks has propagated throughout the network, some valid blocks can be discarded.

Testing by Zakura, Zcash node software developed by Valar Group and Project Tachyon, examined the 25-second interval across 80 computers in 11 regions. Under demanding conditions in which every block contained transactions, approximately 3.43% of mined blocks were discarded, compared with 1.57% under the previous 75-second interval. The results highlight the importance of network coordination as block production accelerates.

NU7 also introduces limits on private transaction activity per block. These restrictions are intended to reduce the amount of blockchain data wallets must download and examine to identify payments addressed to them. According to the upgrade specification, the estimated worst-case daily download requirement falls from 271 megabytes to 169 megabytes. Capacity for simple private payments could increase from approximately three transactions per second to more than six.

Fee Redistribution Addresses Long-Term Mining Sustainability

Another significant component of NU7 is its revised transaction-fee allocation. Miners will receive 40% of transaction fees, while the remaining 60% will be removed from circulation and recorded in a reserve intended to support future mining rewards.

The mechanism is expected to begin returning those accumulated fees through block rewards around February 2031. Its objective is to supplement miner compensation as regular block subsidies decline through Zcash’s existing halving schedule. The arrangement preserves the network’s 21 million ZEC supply cap, rather than introducing an increase in the maximum supply.

Retirement of Sprout Introduces a Separate Asset Consideration

NU7 also retires Sprout, Zcash’s original privacy pool introduced in 2016. Approximately 12,224 ZEC remaining in the legacy pool became unspendable under the upgraded network rules. Although a potential recovery mechanism has been discussed by co-founder Sean Bowe, no recovery proposal had been approved at the time of CoinDesk’s reporting.

Looking ahead, the significance of NU7 will depend on whether faster block production translates into reliable payment experiences, whether wallet synchronization becomes more efficient and whether the revised fee mechanism supports long-term network security. The upgrade strengthens Zcash’s technical infrastructure, but sustained adoption will ultimately depend on how effectively developers, exchanges, merchants and wallet providers integrate the new capabilities.