10 Days Left: Zcash Set to Cut Block Times to 25 Seconds

Zcash is nearing a major network upgrade that will reduce block times from 75 seconds to just 25 seconds. This is another major change to Zcash’s underlying infrastructure.

Network Upgrade 7, scheduled for November 5, will reduce block times from 75 seconds to just 25 seconds, while disabling Sprout transactions. With the activation approaching, users holding ZEC in the legacy Sprout pool are being advised to migrate their funds to the Sapling pool beforehand.

The upcoming change builds on Zcash’s earlier Blossom upgrade, which activated in 2019 and cut block times in half, from 150 seconds to 75 seconds. The upgrade also reduced the 500-block Sprout to Sapling pool migration interval from 20.8 to 10.4 hours.

Ahead of the upgrade, Zcash announced the release of Zebra 7.0.0 on October 22, 2026, the first stable release with support for NU7 on Mainnet.

In light of this, all mainnet operators must upgrade to Zebra 7.0.0 before height 3,543,405 (about Nov 5) to stay on the consensus chain. This is because Zebra 6.4.x stops itself days before activation.

NU7 comes to Mainnet

NU7 brings blocks every 25 seconds instead of every 75, a Network Sustainability Mechanism that recycles part of every transaction fee into future block rewards, and new shielded limits that protect wallets from spam, and is expected to activate in the next 10 days at height 3,543,405, planned for around November 5.

Currently, a Zcash user waits 75 seconds on average for a first confirmation. Under ZIP 218, NU7 slashes the target block spacing to 25 seconds, so the average wait users see is about three times shorter, but the amount of ZEC issued per day stays the same. The NU7 release also brings faster, more reliable syncing near the chain tip and fixes seven security advisories.

Block rewards drop with each halving, and the network will eventually rely on fees to fund its security. NU7 starts preparing for that now. Under ZIP 235, 60% of each block’s transaction fees are removed from circulation and placed in a reserve, while miners keep the other 40%, giving them ample reason to include transactions. Under ZIP 237, blocks will later reissue a small, predictable portion of that reserve in addition to their normal reward; on Mainnet, this begins at height 8,939,664, as specified in ZIP 259. The four-year halving timetable and the 21 million ZEC supply cap are both unchanged.

NU7 introduces per-block limitations to Orchard, Ironwood, and Sapling activity, but no new Sprout JoinSplits. As defined in ZIP 218, these limits more than double Orchard throughput (2.9 to 6.6 transactions per second) while reducing the worst-case sync bandwidth that a spammer can push onto light wallets by about 37%.