In NU7, Zcash Reduces Block Time to 25 Seconds and Changes in Security Funding Mechanism

The NU7 network upgrade for Zcash was activated in early November at block 3,543,405, reducing the target block interval from 75 to 25 seconds. This upgrade also changes how transaction fee rewards contribute to the future security of the network. The reduction in block time will allow users and services to receive confirmations faster, although the actual block arrival time may vary. The new update is not just a software patch: it changes the block creation process and fee handling while maintaining the overall coin issuance structure. According to the Zcash Foundation, node operators must update their clients to a version compatible with NU7 to remain part of the consensus chain after activation. The need for compatible software is critically important to ensure the proper functioning of wallets and services.

In addition to changes in transaction processing speed, NU7 introduces a network sustainability mechanism that directs 60% of transaction fees into a public reserve for future redistribution among miners. The remaining 40% will be available to miners at the time of collection. The goal of this mechanism is to smooth out the eventual decline in security funding as the network matures. This is not an additional profit, and reserving funds for future rewards is not equal to the fees that immediately go to current miners. Evaluating this mechanism requires assessing its interaction with market demand and its ability to achieve the stated security goals.

The upgrade also removes support for older version 4 transactions, which poses certain risks for Zcash validators supporting earlier protocol versions. Network improvements should also be evaluated in terms of wallet compatibility and the availability of shielded payments. The next steps for users and operators include checking node versions and the compatibility of specific wallets with NU7.