Zcash’s NU7 upgrade has reportedly gone live on testnet, starting a path toward a November 5 mainnet target after a planned October 20 review. The current event matters because the reported changes are not cosmetic: they include a shorter target block interval, version 4 transaction deactivation, and a warning that older Sprout-era funds may become unusable if they are not moved before full activation.

Zcash NU7 has reached testnet, but mainnet timing remains conditional

The clearest reading is that NU7 has reached a reported testnet milestone, while the mainnet timeline still depends on a later decision. The current trigger is the claimed testnet activation on October 5, alongside a reported activation-block timestamp of 18:21:45 UTC on October 4. That timing difference can fit a normal split between chain time and announcement date, but it does mean the activation sequence should be described carefully rather than as a single settled timestamp.

What is independently supported is narrower: a Zcash developer planning artifact references NU7, showing the upgrade exists inside the network’s official development pipeline. What is not yet established in the available material is the operational layer around it, including the testnet activation record, the exact readiness process for October 20, and whether November 5 has been formally locked in or remains a target date. The practical takeaway is that NU7 looks active and credible, but the schedule is still better understood as conditional than final.

The reported NU7 rule changes are meaningful, but not yet fully documented

NU7 is being described as a substantive protocol change, not a routine software refresh. The reported package includes cutting Zcash’s target block interval from 75 seconds to 25 seconds, disabling version 4 transactions, and introducing a sustainability mechanism that would direct part of transaction fees toward future block rewards. If implemented as described, those would touch transaction handling, user compatibility, and reward design at the same time.

The limitation is that the available material does not yet provide the full protocol text needed to define those mechanics precisely. Without that layer, it is still unclear how the 25-second target is implemented, how broad the version 4 deprecation is across wallets and service providers, and whether the fee-based sustainability mechanism changes issuance economics or only redistributes fee flows inside the system. That keeps the responsible framing narrow: these are reported components of NU7, and they matter, but they should not yet be stretched into hard claims about throughput, user experience, or reward economics.

Sprout migration is the key user-risk before any mainnet activation

The most consequential part of the current story is the reported warning around older funds, not the performance headline. The stated risk is that once version 4 transactions are disabled, ZEC still sitting in the older Sprout privacy pool would become unusable unless it is moved before NU7 is fully activated. That makes legacy-balance handling the upgrade’s clearest user-impact angle.

The immediate gap is specificity. The available material does not yet define the exact affected balances, the supported migration path, the wallet software that can complete it, or the final deadline mechanism such as activation height. It also does not spell out the exact compatibility implications for exchanges, custodians, or hardware-wallet flows. So the most important next step for anyone tracking NU7 is the first formal operating guidance that turns the warning into a concrete checklist. Until that appears, the schedule matters less than the unresolved question of who is exposed and how they can safely exit the old transaction path.