Zcash Foundation Targets NU7 Testnet Activation at Block 4,465,026 on October 6

Zebra 7.0.0-rc.0 Ships for NU7

The Zcash Foundation has released Zebra 7.0.0-rc.0, the first release candidate for NU7, the network's next major upgrade, and set the testnet activation for around October 6, 2026. The Foundation confirmed that the NU7 code base is complete on the Zebra client, its Rust implementation of the protocol, and called on node operators to upgrade before the activation block. A release candidate is the final testing stage before a tagged production build, so the rc.0 label tells operators the feature set is frozen and what remains is consensus testing on the public network. Executed as a coordinated network fork, the upgrade lands on the public testnet at block height 4,465,026. The mainnet activation height will be chosen on October 20, 2026, which leaves exchanges, wallets and mining pools roughly two weeks to align their plans after the testnet run. The Foundation's official post confirms the schedule and the headline change: under ZIP 218, the target block interval falls from 75 seconds to 25 seconds, and the typical wait for a first confirmation drops accordingly. Daily ZEC issuance stays the same, because blocks arrive more often while each reward is scaled down to keep the supply schedule intact. Shorter confirmations target the delays operators report most often at points of sale, for exchange deposits and on cross-chain bridge flows. Testnet operators face a practical deadline: nodes still running older releases fall out of consensus once block 4,465,026 is reached, so the window before October 6 is the operative one. In our live monitoring, the Zcash (ZEC) price traded about 4.9% lower over the past 24 hours while the upgrade calendar firmed. Positioning has been active around the name as well: on-chain data shows a whale withdrew 2,000 ZEC from Binance into a $66.19 million self-custody wallet, and upgrade news now leads the wider Zcash ecosystem conversation.

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Fee Reserve and Shielded Limits

NU7 also rebuilds how the network pays for its own security. Block rewards shrink at every halving, and the protocol will eventually depend on transaction fees to fund miners; the upgrade builds that bridge now. Under ZIP 235, 60% of each block's transaction fees are withdrawn from circulation into a reserve, while miners keep the remaining 40%, a split designed to keep them including transactions rather than excluding them. Under ZIP 237, every block then reissues a small, predictable slice of that reserve on top of its normal reward, which the Foundation says makes the long-term security budget more predictable. The reserve introduces a new accounting layer the release notes describe as supply neutral: fees move out of circulation, and only a small reissued slice returns. The Foundation stressed that the four-year halving cadence and the 21 million ZEC supply cap are untouched. The second pillar is spam defense for shielded pools, the encrypted transaction sets whose parameters trace back to the Zcash Ceremony trusted setup. NU7 applies per-block limits: a cap of 330 Orchard or Ironwood operations per block, up to 300 Sapling inputs and outputs, a pooled budget of 330 shared across pools, and a ban on new Sprout JoinSplits. These caps bound how much shielded capacity a single block can consume and protect wallets from spam-heavy transaction loads. The demand is not hypothetical: on-chain records show the Bitget hackers shielded 2,700 ZEC worth about $3.8 million in the Ironwood pool, an episode that shows why predictable capacity limits matter for privacy flows. Zcash's shielded design shares ancestry with later privacy systems such as the Aztec Network, while it differs from compact-history designs like Mimblewimble, which trims the chain rather than encrypting transactions. Wallet providers and pool operators can now code against fixed limits instead of estimates, which is what the rc.0 freeze enables. Both camps will watch one metric above all: how the fee reserve behaves under real block load once testnet traffic starts after October 6.

Security Budget Past the Halvings

COINOTAG analysis: read against the official release notes, NU7 is a security-budget blueprint as much as a speed patch. The canonical changes are ZIP 218's 25-second block interval, ZIP 235's 60% fee reserve, ZIP 237's reissuance and the 330 and 300 shielded limits, with testnet activation at block 4,465,026 and the mainnet height fixed on October 20, 2026. For node operators the impact is binary: run the upgraded Zebra client before the activation block or fall out of consensus. Markets have not waited: Grayscale's ZEC ETF logged a first weekly outflow of $93.6 million as the altcoin market repriced. The spam mitigation is already written into the protocol; what remains open is how miners price transactions once 40% of fees replace reward growth.