Shielded Labs Raises Possibility of Delaying Zcash’s Ironwood Upgrade Amid Z3 Migration

Shielded Labs has raised the possibility of delaying Zcash’s Ironwood network upgrade, citing concerns that exchanges, mining pools, wallets, and other ecosystem participants may not have enough time to prepare for the planned activation in late July. According to Cointelegraph, Shielded Labs executive director Jason McGee said in a Zcash community forum post that the upgrade is colliding with a broader infrastructure transition that requires operators to replace Zcash’s longstanding node and wallet software, zcashd, with a new toolset known as the Z3 stack. The situation underscores a trade-off between moving quickly to restore confidence in Zcash’s shielded supply and allowing sufficient time for participants to deploy and audit new infrastructure safely. Ironwood was proposed after researchers identified an “infinity” bug in Orchard, Zcash’s main private transaction pool, which could theoretically have enabled an attacker to create an unlimited amount of counterfeit ZEC inside the pool without detection. Developers said there was no evidence the pool had been exploited, but Orchard’s privacy properties make it impossible to prove that no counterfeit coins were created. Under Ironwood, Zcash would open a replacement private pool and stop new activity in the existing Orchard pool. Funds leaving Orchard would be required to pass through an accounting checkpoint designed to prevent more ZEC from exiting than originally entered, enabling users to verify that circulating supply remains within intended limits. Meanwhile, the zcashd retirement would shift operators to Zebra for running a node, Zaino for providing blockchain data to applications, and Zallet for wallet functions, with official guidance noting some zcashd capabilities may not have direct replacements. McGee said Zallet and Zaino were still under development and not ready for production use, and feedback from infrastructure providers indicated readiness timelines vary, with some expecting to be prepared by late July and others needing more time. McGee said no delay has been finalized. Zcash founder Zooko Wilcox said security reviews had not found additional serious bugs so far and that developers are working to verify the new system ahead of Ironwood’s activation.