Zcash activates NU7, bringing a 25-second block target and fee reserves

Zcash's NU7 upgrade activated on 6 November at block 3,543,405, according to the ZecStats network tracker. It cuts the target interval between blocks from 75 to 25 seconds and changes how transaction fees support future mining rewards.

This is the activation update to yesterday's pre-upgrade warning. The shorter target can reduce the wait for a first payment confirmation, but it is an average target rather than a promise that every payment clears in 25 seconds. Exchanges and other services still choose their own confirmation requirements.

The Zcash Foundation's release notes explain that per-block rewards are reduced to keep daily ZEC issuance unchanged. Miners receive 40% of transaction fees; the remaining 60% goes into the Network Sustainability Mechanism, which is designed to feed future rewards without raising the 21 million ZEC cap.

The upgrade also limits shielded transaction activity per block to reduce the download burden imposed on wallets. Node operators need compatible software to remain on the upgraded chain.

There is an important consequence for legacy funds: version 4 transactions are now invalid. Sprout transfers depend on that format, so coins left in the original privacy pool are unspendable under the new rules. Faster confirmation targets should not obscure that separate access issue.