--- title: "Zcash Sets NU7 Mainnet Height at 3,543,405 as Zebra Tackles Sync Stalls" description: "Developers merged the network upgrade activation block, targeting early November, while the Zcash Foundation addresses testnet node issues before releasing Zebra 7.0.0." url: https://basisdesk.news/news/zcash-nu7-mainnet-height-zebra-sync-fixes published: 2026-10-21T10:21:19.022Z modified: 2026-10-21T10:21:19.022Z section: Altcoins author: Basis Desk Newsroom (AI-generated, source-verified) sentiment: neutral tickers: [ZEC] tags: [Zcash, NU7, Zebra, Network Upgrade, Hard Fork, Mining] license: Quote with attribution to Basis Desk (basisdesk.news). Not financial advice. --- # Zcash Sets NU7 Mainnet Height at 3,543,405 as Zebra Tackles Sync Stalls Developers merged the network upgrade activation block, targeting early November, while the Zcash Foundation addresses testnet node issues before releasing Zebra 7.0.0. ## At a glance - **What happened:** Developers finalized the Zcash NU7 mainnet activation at block 3,543,405, while the Zebra client team began fixing multiple testnet sync bugs. - **Why it matters:** Setting the block height establishes the hard timeline for activating consensus changes and deprecating legacy Sprout transaction features. - **Who is affected:** Zcash node operators, miners, wallet services, and Zebra client users. - **Takes effect:** 2026-11-05 - **What's next:** The release of Zebra 7.0.0 stable following bug fixes, ahead of the target Nov. 5, 2026 mainnet upgrade date. - **Status:** final - **Primary source:** [Tracking: NU7 Mainnet activation readiness](https://github.com/ZcashFoundation/zebra/issues/11674) — github.com ## Key points - Zcash NU7 mainnet activation block is set to height 3,543,405, targeting activation around Nov. 5, 2026. - Zebra developers are resolving sync-stall bugs and peer-banning issues before issuing the 7.0.0 stable release. - The testnet seeder fleet observed roughly 14 of 31 peer groups ready, short of the required 75% activation quorum. ## Editorial remark - **Context:** The Zcash community activated NU7 on the public testnet in early October, setting the stage for faster block times, Sprout address deprecation, and revised funding stream parameters. - **Impact:** Node operators running Zebra must await stable release 7.0.0 to fix known sync stalls, while Sprout address holders must broadcast and confirm sweeps prior to mainnet activation. - **Watch:** Developers must merge primary network stall fixes into Zebra 7.0.0 release candidates ahead of the expected Nov. 5 mainnet target. Developers have formally assigned the mainnet activation block for the Zcash Network Upgrade 7 (NU7) at height 3,543,405, targeting activation around Nov. 5, 2026, according to a merged repository pull request [2]. The approval also fixes the mainnet Non-Sprout-to-Non-Sprout (NSM) reissuance height at 8,939,664 under ZIP 237 and sets the conclusion height for Revision 2 funding streams at 6,132,390 in ZIP 214 [2]. While protocol specifications are finalized, client teams are moving to resolve infrastructure bottlenecks before stable rollouts [1]. The Zcash Foundation opened an epic tracking readiness for Zebra 7.0.0 stable, documenting several node synchronization stalls observed on the public testnet [1]. The NU7 upgrade previously activated on the public testnet at block 4,465,026 on about Oct. 6, 2026, but network tests revealed issues where nodes stopped syncing or tracked losing chain branches during min-difficulty bursts [1]. ## Client Readiness and Node Fixes According to the Zebra tracking document, the network seeder fleet has not yet confirmed consensus on the testnet, reporting only 14 of 31 peer groups ready against a required 75% quorum [1]. Zebra engineers are evaluating fixes for open issues, including near-tip sync stalls caused by busy serving peers, early cache evictions of transparent outpoints, and honest peers being mistakenly banned over lock-time rejections [1]. Three security fixes in a private repository are also queued for inclusion in Zebra 7.0.0 [1]. At the time of writing, $ZEC traded at $1,258, up 11.0% over 24 hours. The upgrade will enforce critical changes, including the migration and deprecation procedures outlined in [earlier protocol drafts](https://basisdesk.news/news/zcash-nu7-upgrade-block-times-sprout-deprecation). Node operators, wallet recovery tools, and institutions that [recently updated infrastructure](https://basisdesk.news/news/gemini-zcash-infrastructure-migration-zakura-nu7) must ensure compatibility before mainnet block 3,543,405 arrives [1] [2]. ## Sources 1. [Tracking: NU7 Mainnet activation readiness](https://github.com/ZcashFoundation/zebra/issues/11674) — github.com, 2026-10-21 2. [Set the NU7 mainnet activation height to 3543405 by ebfull · Pull Request #1405 · zcash/zips](https://github.com/zcash/zips/pull/1405) — github.com, 2026-10-20 --- Basis Desk Newsroom · AI-generated, source-verified · https://basisdesk.news/about/how-we-use-ai