Zcash to Reduce Block Time from 75 to 25 Seconds in NU7 Upgrade

The Zcash network is preparing for the Network Upgrade 7 (NU7), which is expected to activate around November 5, 2026, at height 3,543,405 – within the next 10 days. The main change: block generation time will be reduced from 75 to 25 seconds. Users holding ZEC in the outdated Sprout pool are advised to transfer their funds to the Sapling pool before activation.

The upgrade continues the logic of the Blossom upgrade, which was activated in 2019: at that time, the block time was halved from 150 to 75 seconds. Additionally, NU7 reduces the migration interval from Sprout to Sapling over a span of 500 blocks – from 20.8 to 10.4 hours.

Currently, a Zcash user waits an average of 75 seconds for the first confirmation. According to ZIP 218, NU7 reduces the target interval to 25 seconds, so the average wait time will decrease by about three times, while the volume of ZEC issued per day will remain the same. The upgrade also speeds up synchronization at the chain tip and addresses seven security recommendations.

NU7 introduces a network resilience mechanism. According to ZIP 235, 60% of each block's fees are removed from circulation and placed in a reserve, while miners keep 40% – a sufficient incentive to include transactions. According to ZIP 237, blocks will later reissue a small predictable portion of the reserve beyond the usual reward; on the mainnet, this will start at height 8,939,664, as specified in ZIP 259. The four-year halving schedule and the 21 million ZEC limit remain unchanged.

NU7 also introduces activity limits in each block for the Orchard, Ironwood, and Sapling pools, but no new Sprout JoinSplits appear. According to ZIP 218, these limits more than double Orchard's throughput – from 2.9 to 6.6 transactions per second – and reduce the worst-case synchronization bandwidth that a spammer can impose on light wallets by about 37%.

On October 22, 2026, Zcash announced the release of Zebra 7.0.0 – the first stable release with NU7 support on the mainnet. All mainnet operators must upgrade to Zebra 7.0.0 by height 3,543,405, approximately by November 5, otherwise, they will fall out of the consensus chain: Zebra version 6.4.x will self-disable a few days before activation.