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<p><img width="1200" height="610" src="https://financefeeds.com/wp-content/uploads/2026/09/Zcash-Privacy-Transactions-Hit-a-Four-Year-Milestone.webp" alt="Zcash" title="Zcash Jumps 12% as Developers Propose Block 3,543,405 for 25-Second NU7 Upgrade 32"></p><a href="https://financefeeds.com/zcash-zec-price-1494-kraken-uae-force-liquidation-september-25-bull-1750-bear-1220/" rel="noopener noreferrer nofollow">Zcash</a> (ZEC) climbed nearly 12% over the past 24 hours as developers moved closer to scheduling the network's NU7 upgrade, proposing mainnet activation at block 3,543,405, expected around November 5. The upgrade would cut Zcash's target block time from 75 seconds to 25 seconds, while introducing changes to transaction fees and permanently disabling spending from its original Sprout shielded pool. ZEC was trading around $1,361 during the latest CoinGecko check on October 21, up approximately 11.8% over 24 hours and 16.7% over seven days. Its market capitalization stood near $23.1 billion. The important qualification is that the activation height has been proposed and reviewed, but not yet merged into the project's main specification. Developers have agreed on the intended height, and the pull request received two approvals on October 20. Subsequent revisions followed, and the proposal remains open. 
<h2 id="what-does-block-3-543-405-mean-for-zcash-s-nu7-upgrade">What Does Block 3,543,405 Mean for Zcash's NU7 Upgrade?</h2> Zcash developer Sean Bowe submitted pull request #1405 on October 20, proposing block 3,543,405 as the mainnet activation height for NU7. Based on the network's expected block production, that height corresponds approximately to November 5. The proposal goes beyond selecting an activation block. It also updates related Zcash Improvement Proposals covering network funding streams, monetary issuance and the deployment status of NU7's consensus changes. Two reviewers approved an earlier revision of the pull request on October 20. However, the current GitHub review history records those approvals as dismissed following further changes. The proposal was still open and unmerged during the October 21 evening check. Crucially, the published ZIP-259 deployment specification continues to list the mainnet activation height as undecided. This means November 5 remains the proposed activation date rather than a finalized network commitment. The development follows <a href="https://financefeeds.com/zcash-nu7-testnet-25-second-blocks-mainnet/" rel="noopener noreferrer nofollow">Zcash's NU7 testnet activation on October 5</a>, previously covered by FinanceFeeds. That deployment introduced 25-second target blocks on the public test network ahead of the planned mainnet transition. Moving from a successful testnet deployment to an agreed activation proposal is significant, but final integration into the specification and compatible node software remains necessary. 
<h2 id="how-will-25-second-blocks-change-zcash-transactions">How Will 25-Second Blocks Change Zcash Transactions?</h2> NU7 would reduce Zcash's target block interval by two-thirds, allowing the network to produce approximately three times as many blocks over the same period under normal operating conditions. For users, the clearest benefit is faster confirmation. Three confirmations currently require approximately 225 seconds, or three minutes and 45 seconds, at the 75-second target. With 25-second blocks, the equivalent theoretical waiting period falls to 75 seconds. Actual confirmation times can vary because block production is probabilistic, and exchanges or payment providers may maintain their own deposit confirmation policies. The upgrade also adjusts block subsidies and issuance intervals to preserve Zcash's broader monetary schedule despite more frequent blocks. Another important change involves transaction fees. Under the proposed Network Sustainability Mechanism, 60% of transaction fees would be temporarily removed from circulation and held in a protocol-level balance. Those funds are designed to return through mining rewards beginning around February 2031. The mechanism does not create additional ZEC beyond the intended supply framework; it changes the timing of when some value circulates. The combination of shorter blocks and altered fee distribution makes NU7 both a payment-speed upgrade and a change to the network's longer-term miner compensation structure. 
<h2 id="why-must-sprout-holders-move-their-zcash-before-november-5">Why Must Sprout Holders Move Their Zcash Before November 5?</h2> The most consequential deadline concerns holders of funds in Sprout, Zcash's original shielded transaction pool introduced in 2016. NU7 would prohibit version 4 transactions from its activation block onward. Because Sprout spending depends on that transaction format, funds remaining in the pool when the upgrade activates would become unspendable under the new consensus rules. This is not merely a warning about older wallets becoming inconvenient to use. It is a protocol-level restriction that prevents the affected funds from being transferred afterward. Holders with Sprout balances must therefore complete migration to a supported pool before activation. They should not assume that initiating a transfer shortly before the target block will be sufficient. As <a href="https://financefeeds.com/zcash-sets-a-deadline-that-could-lock-funds/" rel="noopener noreferrer nofollow">FinanceFeeds warned in its September 23 report on the Sprout deadline</a>, users who fail to migrate their legacy funds risk permanently losing the ability to spend them. Ordinary ZEC holdings outside Sprout are not subject to the same restriction simply because they use the Zcash network. <strong>Investor Takeaway:</strong> The proposed November 5 upgrade could shorten confirmation times substantially, but Sprout holders face a much more immediate issue: funds must be moved before the activation block or they will become unspendable. 
<h2 id="what-must-happen-before-nu7-is-activated">What Must Happen Before NU7 Is Activated?</h2> The next milestone is the merger of pull request #1405, which would incorporate the proposed activation height and related specification changes into the official Zcash Improvement Proposals. Developers must also complete the necessary protocol specification changes, release compatible software and ensure that node operators, wallets and exchanges are prepared for the transition. The active pull request identifies outstanding protocol specification work, meaning an agreed activation height alone does not establish complete deployment readiness. For Zcash investors, the distinction between an approved proposal and an implemented network upgrade matters. The market can price expectations ahead of activation, but neither the recent ZEC rally nor the proposed date guarantees that the technical rollout will proceed without adjustment. The next verifiable signals are the pull request's merge, publication of the activation height in ZIP-259 and confirmation of compatible node software. Until those steps are completed, block 3,543,405 remains the proposed target. For Sprout holders, however, the prudent deadline is earlier than the activation itself, because waiting until the final block leaves no margin for delayed transactions or migration problems.

Zcash Jumps 12% as Developers Propose Block 3,543,405 for…

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