Zcash NU7 Activation Height Set At 3,543,405 As Zebra 7.0.0 Ships

Zcash's next network upgrade now has a fixed spot on the chain. Zcash NU7 goes live on Mainnet at block 3,543,405. Zebra 7.0.0, published at 02:08 UTC on October 22, is the first stable release that carries it.

Explorers put the chain tip near block 3,526,390 at 06:25 UTC that morning. About 17,000 blocks remain. Blocks are arriving at roughly 1,139 a day. That puts the height about 15 days out. The NU7 timeline thread had given November 5.

What the Zcash NU7 height pull request settled

Pull request 1405 in the zcash/zips repository set the number. It was opened on October 20 and merged at 20:06 UTC on October 21. ZIP 259 now holds the Mainnet height. Its companion ZIPs moved to Proposed status too: 218, 235, 237, 2003 and 2008, plus revisions of ZIP 207 and ZIP 214. That finalizes the Zcash NU7 package.

Other figures follow from the height. ZIP 237 publishes a Mainnet reissuance height of 8,939,664 for the Network Sustainability Mechanism. ZIP 214 states that the Revision 2 funding streams end at height 6,132,390. ZIP 237 also says NU7 trims the current supply cap by about 0.50 ZEC. That leaves it roughly 0.68 ZEC under MAX_MONEY, as agreed on the October 20 ZIP sync call.

The merged pull request that sets the activation height. Source: zcash/zips pull request 1405.

One smaller edit matters for expectations. ZIP 226 no longer says shielded assets are scheduled for NU7. A migration transaction whose validity window crosses activation gets a window of at least about 14.7 days, according to ZIP 318.

Faster blocks and fewer v4 transactions

The NU7 timeline thread on the Zcash forum, opened by ebfull on September 17, lists the headline changes. Blocks get a 25-second spacing under ZIP 218. Version 4 transactions are disabled. The Network Sustainability Mechanism arrives through ZIP 234 in its alternate form and ZIP 235.

Halvings are preserved, the thread says, with reintroduction starting in February 2031. It also states that no new transaction formats appear in this upgrade. Everyday users should notice little from Zcash NU7, while full nodes, indexers and block explorers may need changes.

Testnet went first, with activation scheduled for October 6 at height 4,465,026, per the Zebra 7.0.0-rc.0 release notes. The thread's own checklist put the final Mainnet decision on October 20, which is the day the pull request opened.

Zebra 7.0.0 for node operators

The Zebra 7.0.0 release page on GitHub. Source: ZcashFoundation/zebra v7.0.0.

For Zcash NU7, release notes say Mainnet nodes must upgrade before the activation height to stay on the consensus chain. The build advertises network protocol version 170190. It also moves the database format from v28 to v29, and Zebra 6.x cannot read v29, so a downgrade needs a full resync. Operators coming from 6.x are advised to back up the state/v28 directory first.

This release is supported for eight weeks instead of the usual twelve. It halts about 56 days after its estimated release height. A new migration guide in the same release maps the 135 RPC methods registered by zcashd 6.20.0 to Zebra or Zallet.