Zcash NU7 upgrade: 25-Second Blocks Ten Days Out

The Zcash NU7 upgrade is now about ten days out, and every Mainnet node needs to be ready. NU7 activates at height 3,543,405. Blockchair showed the chain at height 3,532,106 on Tuesday morning UTC, so roughly 11,300 blocks remain, which at today's 75-second target lands around November 5 or 6. Zakura's 1.7.0 announcement estimates about 00:50 UTC on November 6, while the Zcash Foundation's Zebra 7.0.0 post said around November 5. CoinGecko had ZEC near $1,219.76, up about 0.5% on the day, with a market cap near $20.7 billion at 06:03 UTC (09:03 MSK) on October 27.

What actually happened

ZIP 259 is the deployment ZIP for NU7. It packages ZIP 218 (25-second blocks), ZIP 235 (fee split to the NSM), ZIP 237 (later reissuance from the NSM reserve) and ZIP 2008. The Foundation's Zebra 7.0.0 release, posted October 22, is the first stable Zebra build with Mainnet NU7 support. It also fixes seven security advisories and improves syncing near the tip.

Zakura 1.7.0, aimed at Mainnet operators, makes the same point in plain language: earlier Zakura releases will halt before NU7 activates, so upgrade now. Testnet already flipped to NU7 at height 4,465,026, and Zakura's NU7 dashboard has been tracking the fork live. That test run is why the Foundation and Zakura both sound more confident about Mainnet timing than they would after a paper-only upgrade.

Faster confirmations are the user-facing win. Today a Zcash user waits about 75 seconds on average for a first confirmation. Under ZIP 218 that drops to about 25 seconds, so the average wait is roughly three times shorter. Issuance per day does not rise with the shorter blocks; the protocol adjusts so the supply schedule stays on track.

The NSM reissuance height on Mainnet is 8,939,664. That is when a small, predictable portion of the fee reserve starts coming back on top of the normal block reward, without raising the ZEC supply cap.

Why the Sprout line matters

This is the upgrade detail that can strand money. Sprout transfers only exist as version 4 transactions. Once NU7 activates and version 4 is invalid, those funds cannot be spent. Users who still hold ZEC in the Sprout pool need to migrate before the activation height.

There are also per-block shielded limits and a hard stop on new Sprout JoinSplits. ZIP 218 says those limits more than double Orchard throughput while cutting the worst-case sync bandwidth a spammer can push onto light wallets.

Faster blocks are the headline. Unspendable Sprout funds are the gotcha.

What node operators should do

Upgrade. The Foundation says all Mainnet operators must move to Zebra 7.0.0 or another NU7-ready client. Zakura users should be on 1.7.0. With roughly ten days left, waiting until the day before activation is how you end up on a dying peer set. Zebra 7.0.0 is supported for eight weeks from release, which is enough runway for NU7 but not a reason to delay the install.

Fee economics also change. Miners still have a reason to include transactions, because they keep 40% of fees, while 60% starts filling the NSM reserve that ZIP 237 will later tap. That is long-run chain security planning, not a short-term price catalyst.

We covered Zcash's meme and market side in ZEC-paired memecoins, and another chain's big upgrade in Solana Alpenglow activation. The Zcash NU7 upgrade is a protocol change with real user action items, not just a narrative.

What to do as a reader

If you run a node ahead of the Zcash NU7 upgrade, install Zebra 7.0.0 or Zakura 1.7.0 and confirm your peers will follow height 3,543,405. Check the Zebra release notes and the Zakura 1.7.0 announcement.

If you still have Sprout funds, migrate them now. After activation they are unspendable under the published rules.

If you only hold ZEC on an exchange, ask the exchange whether it has upgraded. The coin's price can move on upgrade news, but an exchange that misses the fork is a worse problem. Nothing here is investment advice.

Sources: Blockchair Zcash explorer, ZIP 259, Zebra 7.0.0, Zakura 1.7.0 and Zakura NU7 page.