Zcash Upgrade Countdown: Block Generation Speed Triples, $16M in ZEC May Be Permanently Frozen

Author: TechFlow

TechFlow Summary: On November 5, 2026 (Beijing Time), the privacy blockchain Zcash confirmed that network upgrade NU 7 will be officially activated at block height 3,543,405. According to reports, this upgrade will not only compress the on-chain target block time directly from 75 seconds to 25 seconds, but also completely decommission the version 4 transaction format, causing approximately 12,226 ZEC currently stuck in the first-generation privacy pool Sprout (totaling about $16 million USD) to lose all transfer channels and face indefinite blocking at the protocol level.

First-Generation Privacy Pool Technical Liquidation, Version 4 Transaction Format Ends

One of the core changes in the NU 7 upgrade is the removal of underlying compatibility support for the version 4 (v4) transaction format. This transaction format is currently the only technical channel for funds to exit the first-generation privacy pool Sprout, which launched in October 2016. With the arrival of the upgrade block height, full nodes will directly refuse to pack any transfer requests based on the v4 format. Even if the owner of the holding address fully possesses a valid private key, the system will no longer provide an effective signing and broadcasting verification path for this privacy pool.

Early zero-knowledge proof technologies carried a heavy technical burden. The Sprout privacy pool relied on the original Trusted Setup established in 2016, where proof generation required substantial memory and time. As subsequent privacy pools like Sapling and Halo 2-based trustless Orchard were deployed, the Zcash core development team advanced technical debt cleanup, opting to directly sever maintenance compatibility with the first-generation architecture and completely strip away outdated cryptographic lines.

Tens of Millions in Dormant Assets Accumulate, Final Window to Escape the Cliff

On-chain statistics show that approximately 12,226 ZEC remain accumulated in the Sprout privacy pool. At a market price of roughly $1,300 per ZEC, the total value of the accumulated funds reaches approximately $16 million. Although advance notice of the network upgrade was issued, large-scale transfer movements of these funds had already plateaued on the eve of the deadline.

Over the past week, approximately 10,037 ZEC were migrated out of the first-generation privacy pool through emergency channels, with a single-day net outflow of 9,094 ZEC on Sunday alone. As of Wednesday, the daily asset outflow had plummeted from its peak to merely around 40 ZEC. The sharp decline in the outflow curve reflects that current holders of the remaining funds failed to respond to the upgrade window; the vast majority of the accumulated tokens belong to static dormant assets from early lost private keys, disconnected owners, or stagnant cold storage.

Specifications Retain Theoretical Patch, Assets Fundamentally Frozen Indefinitely

For the stranded accumulated assets that cannot be migrated, the developer community passed the ZIP 2003 improvement proposal. This specification reserves interface space within the protocol logic for future new withdrawal mechanisms, allowing the network to restore redemption of assets within the Sprout pool via secondary upgrades in the distant future. However, the engineering team attached explicit warnings to the specification text, clearly stating that this interface only has theoretical feasibility and the stranded assets will most likely never be extractable again.

In the generational transition of privacy assets, Zcash has officially completed its leap from Sprout to modernized liquidity pools. Currently, the vast majority of active privacy transfers are concentrated in the Orchard and Sapling pools. The retirement of the old pools ensures the security of existing users' funds while achieving complete isolation of the protocol attack surface from the older era.

Block Time Compressed to 25 Seconds, On-Chain Throughput Restructured at Double Speed

Alongside the technical debt cleanup, NU 7 structurally adjusted the block time parameters for the entire Zcash network. The network-wide target block time was directly compressed from the original 75 seconds to 25 seconds, increasing the single-block generation speed to three times the previous rate. The significant reduction in block time directly decreased users' wait times for block packing when sending privacy transactions, thereby lowering on-chain settlement latency.

The final countdown for the network upgrade activation is locked at block height 3,543,405, with all network nodes waiting for the broadcast of blocks at this height to complete the instant switching of consensus rules.