Key points

  • Zcash ecosystem teams have set October 6 for testnet activation and are targeting November 5 for NU7 on mainnet.
  • The draft upgrade would cut target block spacing from 75 seconds to 25 seconds while reducing the subsidy per block to preserve issuance over time.
  • A final mainnet activation decision is scheduled for October 20, so the November date is a target rather than a completed deployment.

Zcash developers and ecosystem organizations have agreed on a timeline for the network's next major upgrade, NU7, with testnet activation scheduled for October 6 and a mainnet target of November 5. The plan would reduce the proof-of-work blockchain's target block spacing from 75 seconds to 25 seconds, aiming to shorten the wait for confirmations used in payments, exchange deposits and bridge transactions. The upgrade is not live, and its November mainnet date remains subject to an October review.

A staged path to mainnet

The timeline posted on the Zcash Community Forum calls for feature code to be ready by September 30. Testnet activation would follow on October 6, giving teams two weeks to observe the software before a final mainnet decision on October 20. The activation height would then be set for November 5 if the testnet experience supports proceeding. That sequence matters because the current announcement establishes an engineering target, not an irreversible network change.

Related reporting: Zcash holders back 25-second blocks while keeping halving schedule

What 25-second blocks would change

Draft specification ZIP 218 proposes cutting average target spacing by two-thirds. Its authors say a first confirmation would therefore be expected after roughly 25 seconds rather than 75 seconds, although proof-of-work block arrival remains variable and applications may still require multiple confirmations. The same proposal adds global and per-pool action limits intended to cap processing and shielded-wallet synchronization costs while allowing more Orchard transactions over time. The existing two-megabyte block-size limit would remain.

Issuance is designed to remain steady

Producing three times as many blocks does not mean the plan creates ZEC three times faster. ZIP 218 would divide the post-Blossom per-block subsidy by an additional factor of three and extend the halving interval from 1.68 million to 5.04 million blocks. Those adjustments are intended to keep issuance per unit of time effectively unchanged, apart from a small rounding difference described in the draft. Miners would receive smaller rewards more frequently rather than a larger annual allocation.

Network sustainability enters the scope

NU7 is also expected to integrate a Network Sustainability Mechanism. Draft ZIP 235 would remove at least 60% of transaction fees from circulation while leaving the rest available under existing rules, with the removed amount intended for later algorithmic reissuance through block subsidies rather than a permanent burn. Ecosystem organizations aligned on beginning that reissuance in February 2031 after a coinholder poll strongly favored preserving the current halving schedule and delaying the start date. Both ZIP 218 and ZIP 235 still carry draft status.

Who needs to prepare

The forum notice says NU7 does not introduce new transaction formats and should not materially affect ordinary wallets. Full-node operators, miners, indexers and block explorers face more direct changes because the upgrade alters consensus timing, block-count parameters and action limits. Exchanges and payment services will also need to decide whether confirmation-count policies should change; a shorter target interval does not by itself eliminate reorganization risk.

What remains uncertain

The schedule depends on implementation readiness and testnet results. Engineers must still complete the code, choose activation heights and confirm that network behavior matches the proposal's security assumptions. The October 20 checkpoint could preserve, revise or delay the November target. For now, the development is a coordinated upgrade plan with defined milestones—not proof that 25-second blocks are already operating on Zcash mainnet.

Sources

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