Zcash NU7 Upgrade Goes Live, Slashing Block Times From 75 Seconds to Just 25 Seconds

Zcash activated the NU7 network upgrade on mainnet on Nov. 5 at block height 3,543,405, reducing target block times from 75 seconds to 25 seconds. The upgrade also triples the number of blocks between halvings and adjusts block rewards to keep new ZEC entering circulation at roughly the same rate. It introduces Shielded Labs’ Network Sustainability Mechanism, under which 60% of transaction fees are removed from circulation and gradually reissued through future block rewards starting at block 8,939,664, expected in 2031, while maintaining the 21 million ZEC supply cap. NU7 disables version 4 transactions, making about 12,224 ZEC in the Sprout pool unspendable; a separate proposal would have Zcash Community Grants contribute 50,000 ZEC from its treasury to the mechanism.