Zcash has activated its NU7 network upgrade on mainnet, cutting the protocol’s target block interval from 75 seconds to 25 seconds and changing several rules governing shielded transaction capacity, fees and legacy transactions. NU7 became active at block 3,543,405 on November 6, giving Zcash a target confirmation cadence three times faster than before. The activation follows months of technical preparation and community coordination around the network’s next major protocol phase.
The deployment is confirmed by canonical block 3,543,405 and the official NU7 deployment specification, which assigns that height to mainnet. The 25-second figure is a protocol target rather than a guarantee that every block arrives precisely 25 seconds apart. ZecBlock data observed after activation showed an average interval of about 28 seconds, compared with approximately 75.4 seconds before NU7, illustrating that actual block production still varies around the target.
Faster Blocks Expand Shielded Capacity
The shorter interval is intended to reduce the time users wait for confirmations without changing Zcash’s underlying privacy model. Under ZIP 218, the target wait for a first confirmation falls from 75 seconds to 25 seconds, while the protocol adjusts issuance per block so that producing roughly three times as many blocks does not accelerate the scheduled creation of ZEC. Remaining halving intervals are correspondingly extended to preserve the approximate four-year issuance schedule.
NU7 also introduces per-block limits on shielded actions rather than simply tripling the amount of activity wallets may need to process. According to the Zcash Foundation’s Zebra 7.0.0 release, the new limits raise theoretical Orchard throughput from about 2.9 to 6.6 transactions per second while reducing worst-case shielded synchronization bandwidth by roughly 37%. The distinction matters because higher protocol capacity does not by itself establish higher real-world transaction demand.
Wallet behavior continues to determine how much of the faster block cadence users actually experience. Existing wallet guidance recommends multiple confirmations before certain received funds or change can be spent, meaning a 25-second block target does not translate directly into 25-second spendable settlement in every interface. NU7 reduces the time between confirmation opportunities, while wallet policies remain a separate operational layer. The upgrade also strengthens Zebra’s role in network infrastructure, an area already identified as a priority during the Zcash Foundation’s recent leadership transition.
NU7 Changes Fees and Retires Sprout Spending
NU7 also activates a new transaction-fee mechanism. Under ZIP 235, 60% of transaction fees in each block are removed from circulation while miners retain the remaining 40%. Those removed funds form part of the Network Sustainability Mechanism and are scheduled to begin returning algorithmically through future block subsidies at mainnet height 8,939,664. The mechanism does not raise Zcash’s 21 million ZEC maximum supply because future issuance corresponds to value previously removed from circulation.
That fee architecture adds a protocol-level component to Zcash’s broader work on transaction economics, alongside separate proposals exploring more dynamic fee policies. NU7’s fee rule is already a consensus change, whereas other fee-policy proposals remain separate development tracks. Keeping those distinctions clear is particularly important as Zcash combines performance changes with longer-term work on network sustainability.
The upgrade also makes version 4 transactions invalid. Because Sprout transfers cannot be represented using the newer supported transaction formats, ZEC remaining in the original Sprout shielded pool becomes unspendable after NU7 activation. This is more consequential than simply deprecating old wallet functionality: it closes the transaction path required to move those legacy funds. The change arrives after a year in which Zcash developers have also worked through other privacy-pool changes, including the separate Ironwood upgrade proposal.
NU7 therefore combines several distinct protocol changes rather than functioning only as a block-speed upgrade. Its measurable effects are faster target blocks, greater bounded Orchard capacity, a new fee-allocation mechanism and the end of spendability for remaining Sprout funds. Those changes now operate on mainnet following a governance process that included community and coinholder input around NU7, moving the upgrade from proposal and testnet stages into active consensus rules.