Zcash, a proof-of-work network built around zero-knowledge proofs for shielded payments, activated its NU7 network upgrade on November 6 at mainnet block 3,543,405, mined at 02:34 UTC. The activation cut the target block interval from 75 seconds to 25 seconds and brought changes to mining rewards, transaction fees, and shielded transaction processing. It also disabled an older transaction format, leaving funds in Zcash's original Sprout pool unspendable.

Target Block Time Falls to 25 Seconds

Under Zcash Improvement Proposal 218, NU7 reduces the target waiting time for transaction confirmations by two-thirds. Under the previous rules, blocks arrived approximately every 75 seconds. The new target of 25 seconds could shorten confirmation delays for exchanges, wallets, and payment services. An exchange requiring three confirmations, for instance, could see its expected waiting time fall from 225 seconds to 75 seconds, although individual platforms determine their own confirmation requirements.

The network initially operated above the new target. According to ZecStats data, the first 225 post-activation blocks averaged approximately 39 seconds by 04:59 UTC. As in other proof-of-work systems, actual intervals fluctuate around the target because block discovery is probabilistic, with difficulty adjustments intended to steer the average back toward the goal.

Separately, CoinCentral examined ZEC trading activity and ETF flows surrounding the NU7 activation on November 6. Those market observations do not establish that the upgrade caused price changes.

NU7 also raises Orchard's theoretical transaction capacity from about 2.9 to 6.6 transactions per second. The improvement comes alongside limits on shielded activity within individual blocks. The Zcash Foundation estimates these limits reduce worst-case lightweight wallet synchronization bandwidth by approximately 37%, restricting excessive shielded activity that could otherwise increase wallet processing requirements.

Subsidy Cut Keeps Issuance on Schedule

NU7 lowers the scheduled block subsidy from 1.5625 ZEC to approximately 0.52083333 ZEC. The reduction offsets the higher number of blocks produced under the new target interval, meaning planned daily issuance remains approximately unchanged. This differs from NEAR Protocol's recently approved issuance reduction proposal, which targets lower annual token creation over two years.

The upgrade also introduces a Network Sustainability Mechanism under ZIP 235. The mechanism removes 60% of transaction fees from circulation, while miners retain the remaining 40%. The withheld fees are not permanently burned. Instead, the protocol accounts for them as funds eligible for future issuance. Under ZIP 237, reissuance begins at mainnet block 8,939,664, expected around February 2031. The mechanism preserves Zcash's four-year halving timetable and its 21 million ZEC supply cap.

Sprout Disabled and Legacy Funds Locked

Another major change affects Sprout, Zcash's original shielded transaction protocol, which dates to the network's 2016 launch and was later joined by the Sapling and Orchard shielded pools. Under ZIP 2003, version 4 transactions became invalid when NU7 activated, preventing transfers from the Sprout pool under the new consensus rules.

ZecStats recorded approximately 12,224.21 ZEC remaining in Sprout following activation. Those funds are currently unspendable but have not been permanently burned, and no approved recovery mechanism currently allows holders to access them. Any change to that status would itself require a new consensus rule adopted through Zcash's network upgrade process. The transaction restriction extends beyond Sprout: other systems still creating version 4 transactions must migrate to supported formats. Versions 5 and 6 remain valid, and NU7 does not introduce an additional transaction format or shielded pool.

Node Operators Required to Run Compatible Software

The Zcash Foundation's October 22 software release required mainnet node operators to upgrade to Zebra 7.0.0 before activation. Older versions cannot follow the upgraded consensus chain. The release also included seven security advisories and synchronization improvements.

Zcash's rollout follows other recent blockchain infrastructure changes. A November 4 report on THORChain restoring Zcash swaps described a separate protocol update that reinstated trading across several networks. For Zcash infrastructure providers, NU7 changes consensus requirements immediately, while actual payment availability still depends on compatible software, network performance, and each service's confirmation policies.