Zcash Sets July 28 Ironwood Upgrade to Secure Network After Orchard Vulnerability

Zcash developers have confirmed that the network's highly anticipated Ironwood upgrade will be activated on July 28, marking a major security milestone following the discovery of a critical flaw in the blockchain's Orchard shielded transaction pool.

The network upgrade, also known as NU6.3, is designed to permanently retire the existing Orchard pool, prevent any further transactions within it, and introduce a brand-new private pool for shielded transfers. Before funds can enter the new Ironwood pool, they must pass through a verification checkpoint, a process that could help determine whether the recently disclosed vulnerability was ever exploited to generate counterfeit ZEC.

Zcash core developer Sean Bowe confirmed the activation timeline, stating that the community's major ecosystem participants have agreed to launch the upgrade at block height 3,428,143, expected to occur around 8:00 a.m. EST on July 28.

The final activation date comes after discussions within the ecosystem over whether the rollout should be delayed. Earlier, Shielded Labs expressed concerns that exchanges, wallets, and mining pools might not have enough time to prepare for the transition if the upgrade proceeded on its original July 21 target. The one-week delay provides additional preparation time while keeping the deployment on schedule.

Beyond improving security, Ironwood could also play a key role in determining whether the Orchard bug was ever abused. As users migrate their holdings into the new private pool, any illegitimate coins created through the vulnerability would face increased scrutiny. According to Shielded Labs, anyone attempting to transfer counterfeit funds would risk exposing their existence during the migration process, while leaving them behind could render those assets permanently unusable.

The Orchard vulnerability became public in early June and triggered a sharp market reaction. Following the disclosure, ZEC fell by roughly 50%, dropping from over $600 to below $300 before gradually recovering in the weeks that followed. The token has since regained a significant portion of those losses and was recently trading near $493.

Separately, the privacy-focused cryptocurrency reached another important milestone this week. More than 80% of Zcash's fixed maximum supply of 21 million ZEC has now been mined, with the circulating supply surpassing 16.8 million coins, highlighting the network's continued progression toward its long-term issuance cap.