Zcash NU7 officially launched on the test network two days early
This upgrade reduces the gap between target blocks from 75 seconds to 25 seconds, disables version 4 transactions, and introduces the Network Sustainability Mechanism, whereby approximately 60% of transaction fees are transferred to a reserve fund.
10/5/20264 min read
Why was it activated earlier than expected?
This type of network upgrade is tied to block height rather than specific dates, and that difference explains the two-day gap between the estimate and the actual event.
The Zcash Foundation released Zebra 7.0.0-rc.0 on October 2nd with a pre-compiled test network activation height, instructing operators to upgrade before block 4,465,026 to remain on the NU7 chain, and the release notes estimated this to be around October 6th. Valar Group and Project Tachyon, the builders of Zakura, the second node deployment version, established the same activation level in version 1.6.0.
The test network operators upgraded in a timely manner, and the chain reached this height faster than expected. Estimating the activation date based on height is a prediction of block production speed, and block creation times on test networks are more difficult to predict than on the main network because hash rates on test chains fluctuate more.
The practical consequences are minor for the test network and noticeable for the mainnet. When deciding on October 20th as the mainnet's elevation, any accompanying dates on the calendar will be estimates based on projected block output, not a fixed date.
The deadline for converting Sprout does not yet have a specific date.
The most important detail regarding the Sprout migration alert, which most articles overlook, is that no mainnet activation level has been established yet, so a deadline for migrating Sprout to the mainnet doesn't exist as a specific date. November 5th is the target the developers are aiming for. This isn't a scheduled deadline, and the review on October 20th could change it based on what the test network shows.
This means that for anyone holding Sprout ZEC, the window is currently open and there will be a fixed advantage on October 20th, when the activation level is set. Considering October 20th as a more realistic planning deadline than November 5th is a safer approach, because once the activation level is announced, the remaining time is fixed and determined by block production, not by anyone's convenience.
Sprout funds are not lost during the upgrade process. The proposed implementation leaves open the possibility of restoring access later, which would require a future upgrade to restore some spending mechanisms from the pool. It also warns that holders may never be able to spend any remaining funds. Both statements are accurate and should be read together: the funds remain on the blockchain, the ability to transfer funds does not, and whether or not the funds are returned depends on no one's decision. Only funds in Sprout wallets are subject to this restriction. Older wallets may contain Sprout ZEC, transparent ZEC, or both, and the balance in transparent wallets is unaffected.
The trade-offs that the maintainers have made
Approximately 22,621 ZEC represents only a small fraction of the total supply, though it's not a small number. At the price above $1,200 that ZEC reached in September, the ZEC in the pool would be worth approximately $27 million. The choice facing maintainers is whether to continue maintaining the old protected pool indefinitely to preserve access to such a large inactive balance, or to set a final transition timeframe and remove it.
That calculation wasn't abstract for Zcash this year. In May, independent researcher Taylor Hornby revealed an integrity vulnerability in Orchard's proof-of-concept circuit, a flaw that had existed since the pool was activated in 2022 and could allow the creation of unlimited amounts of counterfeit ZEC without a trace on the chain. Because the protected balance was inherently unverifiable, developers couldn't determine if it had ever been exploited. The solution was Ironwood, activated on July 28, which sealed Orchard behind a mechanism limiting withdrawals to verifiable deposits and transferred approximately 3.66 million ZEC to a new pool.
Each protected crypto pool that a network maintains is a separate cryptosystem that needs protection, and its supply cannot be independently audited. Sprout is the oldest pool, built on the original foundation from 2016. Removing it would eliminate a layer of protection that very few people still use, the same logic that created Ironwood, applied to the previous generation. Whether that justifies wasting the money of holders who didn't receive timely warnings is a truly contentious issue, and the discussion on the community forums reflects that.
Assessment and Conclusion
Developers had about two weeks of real-world data before the October 20th decision, and the specifics of the tests during this phase were more operational than theoretical. Exchanges and wallet operators needed node software that supported NU7, and infrastructure providers had been preparing test network updates since October 5th. Block explorers, indexers, and any services that build or analyze transactions needed to handle the v4 removal and tripled block creation speed. The test network was where incompatibilities were discovered, not encountered on the mainnet.
Changes in block creation speed carry the biggest operational weight for third parties. Confirmation counting services will see them arrive three times faster, while each confirmation represents approximately one-third of the proof-of-work. Exchanges that maintain the confirmation requirement will credit deposits faster with less reorganization drag per confirmation, and those that triple the requirement will bring deposit times back to near current levels. It's a policy decision each exchange makes for itself, and the testing phase is when those decisions should be made, not after the mainnet launch. NU7 doesn't add any new transaction formats, so the impact on wallets will be minimal. Full nodes, explorers, and exchanges handle this.
Disclaimer: The content in this article is for informational, research, data analysis, and reference purposes only regarding the cryptocurrency market. All opinions, assessments, forecasts, or opinions reflect the author's perspective at the time of publication and do not constitute investment advice, solicitations for buying or selling, trading recommendations, advertising, marketing, or promotion of any financial products, services, or cryptocurrencies. Mentions of projects, tokens, protocols, exchanges, wallets, or cryptocurrency service providers (CASPs) are for research, analysis, or informational purposes only and should not be construed as endorsements, recommendations, or guarantees in any way. HCCVenture does not broker, advertise, market, promote, or connect users in Vietnam with any cryptocurrency services from CASPs. HCCVenture does not accept asset custody, investment mandates, manage assets, or execute transactions on behalf of clients. All investment decisions are made entirely through the reader's own research (DYOR), evaluation, and responsibility; HCCVenture is not liable for any losses or damages arising from the use of or reliance on the information presented in this article.
Compiled and analyzed by HCCVenture
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