Zcash Activates NU7 Upgrade, Tripling Block Generation Speed

Zcash, the privacy-focused cryptocurrency, has completed a major network upgrade that sharply boosts transaction processing speed.

CoinDesk reported on November 6 that Zcash activated its NU7 upgrade at 2:34 a.m. UTC at block height 3,543,405. The key change cuts the target block generation interval to 25 seconds from 75 seconds, making privacy payment confirmations up to three times faster.

The real-world impact is clear. Merchants can receive a first payment confirmation in about 25 seconds on average. For exchanges that require three confirmations, wait times fall to about 75 seconds from about four minutes.

The upgrade also improves technical stability. Zebra, Zcash node software developed by the Electric Coin Company and the Tachyon project, was pre-tested in a 25-second block environment on 80 computers across 11 regions. During the process, the block orphan rate rose to 3.43% from 1.57% in the previous 75-second environment, but software optimizations reduced the load by cutting repeated computations.

A limit was also set on privacy transaction capacity per block. Under a worst-case scenario, the upgrade specification estimates daily download demand will drop to 169 megabytes from 271 megabytes. It also projects that basic privacy payment throughput will more than double to more than six transactions per second from about three.

The fee structure is changing as well. Miners will receive 40% of transaction fees, while the remaining 60% will be removed from circulation and accumulated in a separate reserve. That reserve is scheduled to be used for future block rewards starting in February 2031, while Zcash's total supply cap of 21 million tokens will remain unchanged.

The upgrade also officially retires Sprout, Zcash's first privacy pool, which launched in 2016. As a result, about 12,224 ZEC became unusable. Co-founder Sean Bowe has proposed a recovery plan, but no official solution has been approved.