Author: Deep Tide TechFlow

Deep Tide Overview: On November 5, 2026, Beijing time, the privacy public chain Zcash confirmed the official activation of the network upgrade code-named NU 7 at block height 3,543,405. According to reports, this upgrade will not only compress the on-chain target block time from 75 seconds to 25 seconds but will also completely discontinue the version 4 transaction format, causing approximately 12,226 ZEC (total estimated value of about 16 million USD) currently stranded in the original Sprout privacy pool to lose all transfer channels, facing an indefinite blockage at the protocol level.

Technical liquidation of the original privacy pool, termination of version 4 transaction format

One of the core changes of the NU 7 upgrade is the elimination of underlying compatibility support for the version 4 (v4) transaction format. This transaction format is currently the only technical channel for transferring funds out of the original Sprout privacy pool, which launched in October 2016. As the upgrade block height arrives, full nodes will directly reject any transfer requests based on v4 format. Even if the holder of the coin fully controls a valid private key, the system will no longer provide a valid signing and broadcasting verification path for this privacy pool.

Early zero-knowledge proof technology carried a heavy technical burden. The Sprout privacy pool relied on the original trusted setup established in 2016, and the proof generation required significant memory and time consumption. With the subsequent launches of the Sapling and Orchard privacy pools based on Halo 2, which do not require a trusted setup, the Zcash core development team is advancing the clearing of technical debt by choosing to directly sever maintenance compatibility with the original architecture, completely stripping away outdated cryptographic pathways.

Tens of millions in dormant assets, final window to escape the cliff

On-chain statistics show that approximately 12,226 ZEC remain dormant in the Sprout privacy pool. At a market price of about 1,300 USD per ZEC, the total market value of the funds stranded in the pool is about 16 million USD. Although the network upgrade announcement was made in advance, large-scale transfer actions of these funds have tended to come to a standstill as the deadline approached.

In the past week, approximately 10,037 ZEC were migrated out of the original privacy pool through an emergency channel, with a single-day net outflow of 9,094 ZEC on Sunday. By Wednesday, the daily asset outflow had sharply dropped from its peak to only about 40 ZEC. The sudden decline in the outflow curve reflects that the holders of the remaining funds have failed to respond to the upgrade window, with the majority of the stranded tokens belonging to early users who lost their private keys, have gone missing, or are in static dormant tokens kept in cold storage.

Specification reserved theoretical patch, assets effectively trapped in permanent freeze

For the stranded assets that cannot be migrated, the developer community has passed the ZIP 2003 improvement proposal. This specification reserves interface space in the protocol logic for the new extraction mechanism that may be developed in the future, allowing the network to potentially restore the redemption of assets in the Sprout pool through a secondary upgrade in the long term. However, the engineering team included a clear warning in the specification text, explicitly stating that this interface only has theoretical feasibility, and the stranded assets are highly likely to never be retrievable.

In the generational transition of privacy assets, Zcash has officially completed the leap from Sprout to modernized funding pools. Currently, the vast majority of active privacy transfers are concentrated in the Orchard pool and Sapling pool, and the retirement of the old pool has achieved a comprehensive isolation of the attack surface of the old protocol while ensuring the security of the majority of existing user funds.

Block time compressed to 25 seconds, on-chain throughput achieves accelerated reconstruction

While clearing technical debt, NU 7 has structurally adjusted the block time parameters of the entire Zcash network. The target block time for the entire network has been directly compressed from the original 75 seconds to 25 seconds, with block generation speed increased to three times the previous rate. The significant reduction in block time directly decreases the waiting time for users in sending privacy transactions and reduces on-chain settlement delays.

The final countdown to the activation of the network upgrade is locked at block height 3,543,405, and the entire network nodes are awaiting the broadcast of the block at this height to complete the instantaneous switch of consensus rules.