Zcash activates NU7 network upgrade on testnet ahead of November mainnet launch

Zcash has activated its major NU7 network upgrade on the public testnet at block 4,465,026, initiating a live rehearsal ahead of a targeted November 5, 2026 mainnet launch. The upgrade cuts target block times from 75 to 25 seconds to enable faster merchant and exchange transactions. It also introduces a Network Sustainability Mechanism that redirects 60% of transaction fees to a future mining reserve and deprecates the legacy Sprout shielded pool, rendering unmoved funds unspendable.

Activation of the NU7 public testnet

• ▪Zcash activated its NU7 network upgrade on public testnet at block height 4,465,026 on October 4, 2026, two days before the October 6, 2026 Zcash Foundation's projected date
• ▪The Zcash NU7 public testnet trial uses valueless coins to allow developers and infrastructure operators to rehearse the NU7 upgrade and validate their software

Timeline for NU7 mainnet activation

• ▪The target date for the Zcash NU7 mainnet activation is November 5, 2026, though no mainnet activation block height has been set yet
• ▪Zcash developers plan to review the NU7 testnet results and make a final decision on NU7's mainnet activation and its block height on October 20, 2026

Reduction of target block spacing

• ▪The Zcash NU7 upgrade aims to cut the target block spacing from 75 seconds to 25 seconds
• ▪To preserve the ZEC issuance schedule with faster blocks under Zcash's NU7 upgrade, the scheduled reward per block is reduced to one-third, keeping the daily amount of new ZEC the same
• ▪The Zcash Foundation stated that Zcash's NU7 block time reduction aims to resolve transaction waiting obstacles for point-of-sale merchants, exchange deposits, and cross-chain bridges

Integration of the Network Sustainability Mechanism

• ▪Zcash coinholders voted in September 2026 to begin paying out the NU7 upgrade's Network Sustainability Mechanism reserve through block rewards starting in February 2031
• ▪The Zcash NU7 upgrade integrates a Network Sustainability Mechanism, which redirects 60% of transaction fees to a reserve for future mining rewards while leaving miners with 40%

Retirement of the Sprout shielded pool

• ▪The Zcash NU7 upgrade disables version 4 transactions and retires the Sprout shielded pool, Zcash's oldest privacy system
• ▪Zcash developers and forum participants warned that ZEC funds left in the Sprout shielded pool must be moved before NU7's mainnet activation or they will become unspendable

Debatable claims

• ▪Reducing Zcash's block time to 25 seconds is necessary for commercial viability
• ▪Zcash is justified in making unmoved Sprout pool funds unspendable
• ▪Redirecting 60% of Zcash transaction fees to a reserve unfairly penalizes current miners
• ▪The two-week window between Zcash's NU7 decision and mainnet launch is too short