Zcash sets Ironwood upgrade for July 28 after Orchard bug

Zcash is expected to activate its NU6.3 “Ironwood” network upgrade at block height 3,428,143 on July 28. Summary Ironwood activates at block 3,428,143, replacing Orchard with a separately tracked shielded transaction pool system. The turnstile blocks more ZEC leaving Orchard than entered, strengthening public supply verification after migration. Quantum-recoverable notes support future recovery, but Ironwood does not make Zcash quantum-secure today by itself. The Zcash Foundation’s Zebra 6.0.0 release places the estimated activation near 13:00 UTC and tells every node operator to upgrade before the fork. The upgrade introduces a new shielded pool and a v6 transaction format. It follows the disclosure of a flaw in the older Orchard pool that could have allowed an attacker to create counterfeit ZEC without an obvious public record. Developers patched the flaw through emergency upgrades in June. They said they found “no evidence” of exploitation, but Zcash’s privacy design prevents them from proving that hidden inflation never occurred. Ironwood creates a separately tracked shielded pool According to the Zebra 6.0.0 release notes, Ironwood reuses Orchard’s Action structure and Halo2 p...