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Zcash developers are targeting Nov. 5 for the NU7 mainnet upgrade, which would cut the network’s target block spacing from 75 seconds to 25 seconds and introduce changes to transaction limits and network funding.
The timeline is not final. NU7 is scheduled to activate on testnet on Oct. 6, with developers due to make the final mainnet decision and set the activation height on Oct. 20 after reviewing testnet performance.
NU7 Would Cut Block Spacing From 75 to 25 Seconds
The faster block schedule comes through ZIP-218, which reduces the target interval between Zcash blocks by two-thirds. The proposal is intended to shorten confirmation times while increasing the network’s transaction capacity.
ZIP-218 also introduces global and per-pool action limits. Its current configuration would increase estimated throughput for standard Orchard transactions from about 2.9 transactions per second to 6.6 while reducing worst-case shielded-sync bandwidth for light clients from roughly 270.5 MB to 169.1 MB per day.
Zcash’s daily issuance rate would remain unchanged by the faster block schedule. The subsidy paid per block would be adjusted because blocks would be produced three times as frequently.
NU7 Would Disable Version 4 Transactions
The agreed NU7 scope also includes disabling version 4 transactions as Zcash moves away from the older transaction format.
The upgrade will not introduce a new transaction format. Developers said NU7 should not significantly affect wallets, although full nodes, indexers, and block explorers may require changes to support the new consensus rules and shorter block interval.
Network Sustainability Mechanism Would Start Recycling ZEC in 2031
NU7 is also planned to integrate the Network Sustainability Mechanism using a halving-preserving alternative to ZIP-234 alongside ZIP-235. The selected configuration keeps Zcash’s existing halving schedule while providing a future path for ZEC removed from circulation to return through block rewards.
ZIP-235 requires at least 60% of transaction fees to be removed from circulation, with the remaining portion available to miners. The removed ZEC is intended to be recycled through future block subsidies rather than permanently destroyed.
Under the current NU7 plan, that recycling would begin in February 2031. Code completion is targeted for Sept. 30, followed by testnet activation on Oct. 6. Developers will decide on Oct. 20 whether to set the activation height for the planned Nov. 5 mainnet upgrade.
