--- title: "Zcash Formalizes NU7 Upgrade Deployment Proposal in ZIP 259" description: "The proposal sets Mainnet activation at block 3,543,405, cuts block times to 25 seconds, removes 60% of transaction fees, and invalidates Sprout transfers." url: https://basisdesk.news/news/zcash-zip-259-nu7-deployment-specification published: 2026-11-06T03:01:21.197Z modified: 2026-11-06T03:01:21.197Z section: Altcoins author: Basis Desk Newsroom (AI-generated, source-verified) sentiment: neutral tickers: [ZEC, BTC] tags: [Zcash, Consensus, Hard Fork, Privacy, Tokenomics] license: Quote with attribution to Basis Desk (basisdesk.news). Not financial advice. --- # Zcash Formalizes NU7 Upgrade Deployment Proposal in ZIP 259 The proposal sets Mainnet activation at block 3,543,405, cuts block times to 25 seconds, removes 60% of transaction fees, and invalidates Sprout transfers. ## At a glance - **What happened:** Dev Ojha of Valar Group published ZIP 259, formalizing the consensus deployment terms for Zcash's NU7 upgrade. - **Why it matters:** The upgrade cuts block times to 25 seconds, burns 60% of transaction fees, and permanently deprecates version 4 transactions, making Sprout funds unspendable. - **Who is affected:** Zcash node operators, miners, wallet developers, and holders of legacy Sprout shielded tokens. - **What's next:** Testnet activation at block 4,465,026, followed by Mainnet activation at block 3,543,405. - **Status:** proposed - **Primary source:** [zips/zips/zip-0259.md at main · zcash/zips](https://github.com/zcash/zips/blob/main/zips/zip-0259.md) — github.com ## Key points - ZIP 259 defines Zcash NU7 deployment at Mainnet block 3,543,405 and Testnet block 4,465,026 [1]. - Block target spacing drops from 75 to 25 seconds, while 60% of transaction fees will be burned out of circulation [1]. - Version 4 transactions are permanently disabled, rendering remaining legacy Sprout shielded funds unspendable [1]. ## Editorial remark - **Context:** ZIP 259 formalizes consensus adjustments following August and September 2026 community polls covering block times and issuance preservation. - **Impact:** Node operators, miners, and custody providers must update node software to protocol version 170190, while Sprout pool holders must migrate funds before activation. - **Watch:** Mainnet activation at block 3,543,405 and subsequent NSM reissuance start at block 8,939,664. Zcash developers have published the deployment specification for the upcoming Network Upgrade 7 (NU7) under ZIP 259, authored by Valar Group's Dev Ojha [1]. The proposal confirms the technical roadmap for the major consensus transition, targeting activation on Testnet at block 4,465,026 and Mainnet at block 3,543,405 [1]. At the time of writing, $ZEC traded at $1,312 amid broader market declines, with $BTC changing hands at $76,113. NU7 introduces fundamental consensus modifications, most notably cutting block target spacing from 75 seconds down to 25 seconds via ZIP 218 [1]. To counterbalance validation load and shielded synchronization overhead caused by faster block creation, the upgrade establishes per-pool and global shielded action limits [1]. Financially, NU7 deploys ZIP 235 to pull 60% of transaction fees out of circulation and incorporates ZIP 237 for the Network Sustainability Mechanism (NSM) [1]. NSM reissuance will trigger at Mainnet block 8,939,664, calculated following the third post-NU7 halving, while maintaining the protocol's fixed supply cap [1]. ## Deprecation of Version 4 Transactions and Sprout Funds Unlike previous cycles, NU7 introduces no new transaction format to limit parser and wallet disruption, preserving existing version 5 and version 6 structures [1]. However, ZIP 259 enforces ZIP 2003, invalidating version 4 transactions across the network upon activation [1]. Because legacy Sprout shielded pool transfers can only be encoded via version 4 transactions, any remaining funds inside the Sprout pool will become permanently unspendable once NU7 activates [1]. Wallets must halt constructing version 4 transactions, as re-signing invalid transactions will not restore their validity [1]. ZIP 259 also waives standard upgrade deprecation timelines, allowing operators of unsupported software to stay online and follow an obsolete fork [1]. Nodes compatible with Mainnet NU7 must advertise protocol version 170190 or higher, with upgraded clients configured to gradually disconnect peers running deprecated versions as activation nears [1]. The upgrade notably incorporates revisions to funding streams under ZIP 207, ZIP 214, and ZIP 2008, while excluding contentious alternative issuance mechanisms such as ZIP 233 and ZIP 234 [1]. Earlier reporting noted how teams have readied infrastructure, including when [Gemini migrated Zcash infrastructure to Zakura node](https://basisdesk.news/news/gemini-zcash-infrastructure-migration-zakura-nu7) ahead of NU7. ## FAQ **What happens to Zcash Sprout shielded funds after NU7 activates?** Because NU7 disallows version 4 transactions, and Sprout transfers can only be represented using that format, any funds remaining in the Sprout pool become unspendable after activation. **What software protocol version is required for NU7?** Nodes on Mainnet must run software that advertises network protocol version 170190 or higher to maintain consensus compatibility. ## Sources 1. [zips/zips/zip-0259.md at main · zcash/zips](https://github.com/zcash/zips/blob/main/zips/zip-0259.md) — github.com, 2026-11-06 --- Basis Desk Newsroom · AI-generated, source-verified · https://basisdesk.news/about/how-we-use-ai