Zcash’s NU7 network upgrade has gone live on the public testnet ahead of schedule, reducing the block target from 75 seconds to 25 seconds. The activation occurred on October 5 after the network reached block height 4,465,026 earlier than expected. Zcash Foundation’s Zebra release had originally projected the change around October 6.
The testnet launch allows wallets, exchanges, miners, and node operators to assess compatibility before the proposed mainnet activation on November 5. Faster blocks shorten the average wait for a first confirmation from about 75 seconds to roughly 25 seconds. However, developers stress that a first confirmation is not the same as final settlement, and services may still require multiple confirmations before crediting payments.
ZEC issuance remains unchanged. Despite producing three times as many blocks, the upgrade adjusts block rewards and extends the number of blocks between halvings. Zcash’s roughly four-year halving rhythm and its 21 million ZEC supply cap remain intact. The change is focused on transaction timing, not on accelerating the release of new coins.
NU7 also implements new block-production rules under the Network Sustainability Mechanism described by the Zcash Foundation. Under this structure, 60% of transaction fees enters a reserve for future mining rewards, while miners receive the remaining 40%. The live testnet run is therefore checking reward calculations and shielded-transaction limits alongside the shorter block interval.
Infrastructure participants face different workloads. Full nodes must validate more blocks, miners must build them, wallets must synchronize them, and exchanges must process deposits arriving in quicker succession. Zcash’s shielded transactions use cryptographic proofs, making private activity more demanding to synchronize than transparent transfers. To help manage this, NU7 places limits on shielded actions within each block.
The proposed November 5 mainnet date depends on results from the live run. Developers need to confirm that node implementations follow the same chain, wallets and exchanges can operate at the quicker pace, and no consensus or performance issues emerge. Project Tachyon, Zcash’s longer-term work on recursive proofs and private-payment scalability, is not part of NU7 and remains under development.
