Summary
- Zcash developers report that the Ironwood upgrade is close to being activated on the testnet.
- Efforts are ongoing to establish a formal proof of soundness prior to the network upgrade.
- Shielded Labs highlights that transitioning exchanges, wallets, and mining pools to the new software is the primary challenge for deployment.
In a set of updates shared on the Zcash forum Thursday, developers indicated that the Ironwood upgrade for the privacy-centric cryptocurrency is progressing toward activation, initially on a testnet. This advancement aims to empower users to confirm the validity of its circulating supply following a serious counterfeiting vulnerability revealed last month.
Launched in June, Ironwood is a proposed upgrade for the Zcash network that seeks to implement a new shielded pool and accounting framework, enabling users to verify the network's circulating supply while maintaining transaction confidentiality.
This upgrade is designed to address the uncertainty highlighted by the Orchard vulnerability found in May, which left developers unable to ascertain if counterfeit ZEC had been produced.
The alarm caused by this vulnerability led to a steep decline in the coin's price, which plummeted by over 50% within two days, dropping from above $600 to a low around $300. ZEC has since recovered approximately half of its losses, currently trading at $457, according to CoinGecko data.
Update on Ironwood from @aquietinvestor: https://t.co/KxHnXMr1SH pic.twitter.com/XYCyRndzkh
— zooko🛡🦓🦓🦓 ⓩ (@zooko) July 2, 2026
“At Shielded Labs, our primary emphasis has been on security, particularly through our new initiative, dubbed Zero, aimed at assisting enterprise users such as mining pools, exchanges, and wallets,” stated Zcash co-founder Zooko Wilcox. “We are currently concentrating on the Zero project to help these entities prepare for a secure transition to Ironwood.”
This update follows the discovery by security researcher Taylor Hornby, who utilized Anthropic's Claude Opus 4.8 to identify a four-year-old flaw in Zcash's Orchard shielded pool that could have permitted the creation of unlimited counterfeit ZEC without detection.
Although the developers addressed the bug on June 1, Zcash's privacy features made it impossible to cryptographically verify if it had ever been exploited, prompting Zcash developers to propose the Ironwood upgrade to eliminate that doubt.
Since then, Zcash developers report they have made notable strides in preparing for Ironwood's activation.
“The timely and secure activation of Ironwood on the Zcash mainnet is crucial for our users, alongside the formal verification work we are conducting to assure there are no concerns regarding supply integrity,” Zcash developer Sean Bowe wrote on X on Thursday. He added that “a sufficient hash rate indicates technical readiness for the mainnet upgrade.”
Bowe also expressed concern that some wallets may not be ready for the upgrade on schedule. “However, this does not warrant delaying Ironwood, as there will be adequate alternatives and ample time on the testnet for those who require it,” he concluded.
Jason McGee from Shielded Labs mentioned that the development is concentrating on two simultaneous tasks: the Ironwood (NU6.3) network upgrade and the migration of the Zcash ecosystem from its legacy Zcashd software to the new Z3 framework, which encompasses the Zebra full node, Zaino indexing service, and Zallet wallet.
McGee noted that development is progressing as planned, with testnet activation of the new consensus rules “expected shortly.”
"The current aim is to finalize both initiatives by the end of July,” McGee stated. “Concerning Ironwood, the teams at Project Tachyon, Valar Group, ZODL, the Zcash Foundation, and Shielded Labs have been diligently working and have made significant headway in recent weeks.”
Formal verification of the new circuit is also ongoing, with the objective of completing a proof of soundness prior to Ironwood's activation, McGee added.
He pointed out that the more significant challenge lies in readying infrastructure providers for the switch to the new software stack. Essential Z3 components, such as Zallet and Zaino, are still under development, leaving exchanges, mining pools, and wallet providers with limited time to implement and test everything before Ironwood goes live.
“The consistent feedback we’ve received indicates that achieving both the Ironwood upgrade and the migration to Z3 on the current timeline will be challenging,” McGee explained, noting that a recent survey revealed some respondents felt prepared while others requested more time.
McGee mentioned that several strategies are being explored to minimize deployment risks, including potentially postponing Ironwood, conducting independent third-party security audits before the deployment, or temporarily supporting Ironwood through Zcashd while partners finalize their migration.
"Ultimately, we all share the same goal of activating Ironwood as swiftly as possible while ensuring our partners can securely transition away from Zcashd,” he remarked. “We believe the focus in the coming weeks should be on ensuring that transition is as smooth and secure as possible."