Zcash will activate its Ironwood hard fork on July 28, retiring the Orchard shielded pool and introducing a corrected pool based on the NU6.3 upgrade. According to Zcash founder Zooko Wilcox, the upgrade addresses a flaw discovered by security researcher Taylor Hornby on May 29 that could permit creation of counterfeit ZEC without public record. The bug allowed an attacker to generate additional ZEC within the Orchard pool while concealing the transaction. The Ironwood upgrade, also known as NU6.3, will activate at block 3,428,143 and will seal the old Orchard pool, preventing further transfers except through a turnstile that limits withdrawals to the amount originally deposited. After activation, users will no longer be able to send or receive ZEC within the Orchard pool; funds must be moved to the new pool before the upgrade takes effect. Exchanges and wallet providers are expected to update their software, which may result in temporary suspensions of deposits, withdrawals, or other services. The Zcash team said the network believes the flaw was unlikely to have been exploited, but the privacy of the Orchard pool means that past exploitation cannot be proven with absolute certainty. An AI‑assisted review using Anthropic’s Mythos system found no additional serious vulnerabilities after the original issue was disclosed, and developers are pursuing independent audits and formal verification of the updated cryptographic system. The hard fork does not identify or freeze individual counterfeit coins; its purpose is to prevent any hypothetical excess supply from entering wider circulation. Zcash has moved away from its legacy zcashd client, and providers still completing that migration may require additional time to support Ironwood fully. Users are advised to ensure their wallets support the new pool before the July 28 activation.