Zcash is approaching the activation height for its NU7 network upgrade, which will reduce the network’s target block interval from 75 seconds to 25 seconds while introducing changes to transaction rules and fee allocation.
The Zcash Foundation’s Zebra 7.0.0 release notice sets mainnet activation at block 3,543,405, expected around November 5โ6. A public upgrade tracker showed the chain below that height in its latest available observation, so activation should not yet be presented as completed.
Faster Blocks Do Not Increase Daily ZEC Issuance
NU7 targets a block every 25 seconds, around three times the previous frequency. The block subsidy is adjusted proportionally so the change does not triple the number of new ZEC issued per day or alter the intended 21-million-coin limit.
Shorter intervals may reduce the time users wait for an initial confirmation, although transaction acceptance, network congestion and wallet requirements still affect the experience. A target block interval is not a guaranteed completion time for every transfer.
The Zcash Foundation said full-node operators need software compatible with NU7 before the consensus transition. Operators remaining on outdated software risk following incompatible consensus rules after the upgrade height is reached.
Legacy Sprout Transactions Will Be Disabled
NU7 removes support for version-four transactions associated with the original Sprout shielded pool. Funds remaining in that pool would become unspendable under the new rules unless moved beforehand through a supported mechanism.
A third-party tracker estimated approximately 12,226 ZEC remained in Sprout at its last observation. That number is a time-sensitive estimate, not a verified final tally of funds affected at activation.
The distinction between unspendable and burned is important: an old balance is not necessarily destroyed through an explicit supply-burning operation simply because the network stops accepting the transactions required to move it.
Transaction Fees Gain a Sustainability Mechanism
The upgrade also introduces the Network Sustainability Mechanism, redirecting part of transaction fees away from immediate circulation for later treatment under the protocol. This mechanism should not be described as permanently burning the same share of every fee.
Additional consensus changes include limits intended to reduce the risk of shielded-transaction spam and updated network funding arrangements. These features were developed through the Zcash Improvement Proposal process and incorporated into supported node releases.
The official upgrade documentation makes clear that NU7 does not introduce an entirely new transaction format. That is different from saying existing software can operate indefinitely without upgrade-related testing.
Activation Depends on Block Height, Not the Calendar
The selected block height is fixed, but the exact moment it arrives varies with actual mining intervals. Public estimates place the transition around early November 6 UTC, which can correspond to November 5 in North America.
Users and services handling ZEC should check software compatibility and supported transaction formats instead of relying only on a calendar date. Wallets managing funds in older shielded pools require particular attention.
The event illustrates the importance of distinguishing announced network schedules from observed blockchain states. For coverage of related security considerations, see BlockBriefing’s guide to crypto wallet custody. The next reporting milestone is an observed chain tip at or beyond block 3,543,405 with compatible nodes enforcing NU7.
