Zcash is scheduled to activate its Ironwood upgrade on July 28 at 8:00 PM Beijing time, as confirmed by core developer Sean Bowe. The upgrade will occur at block height 3,428,143, with all major organizations committed to implementing the NU6.3 upgrade. This update addresses a critical vulnerability in the Orchard pool that could have allowed the minting of unlimited counterfeit ZEC. The Ironwood upgrade introduces a new privacy pool using the Orchard protocol, phasing out the old pool. Additionally, it adds a control flag to the zero-knowledge proof circuit, which disables transfers to other users within the pool while maintaining the change function. This measure aims to enhance security and prevent potential exploitation of the system's privacy features.