Zcash activated its Ironwood network upgrade on July 28, sealing the existing Orchard shielded pool and forcing users into a brand-new pool with a zero balance. Roughly $80 million in ZEC crossed into that fresh pool within 24 hours, a strong opening signal for what amounts to a full reset of the network’s privacy infrastructure.

The upgrade wasn’t just a routine feature release. It was a direct response to a critical bug in Orchard’s proof circuit that had gone undetected for four years, one that theoretically could have allowed someone to mint counterfeit ZEC without anyone noticing.

What Ironwood actually fixes

The Orchard shielded pool launched in 2022 and had accumulated between 3.66 million and 3.76 million ZEC by the time it was sealed. At recent prices, that’s somewhere between $1.7 billion and $1.89 billion worth of tokens sitting in a pool with a compromised proof circuit.

The Ironwood upgrade, formally designated NU6.3, activated at block height 3,428,143. It introduced a completely new shielded pool governed by ZIP 2005, which brings two key improvements: formally verified proof circuits and quantum-resilient record-keeping.

The migration mechanism is called a “turnstile,” and it works exactly like it sounds. Users move funds from the sealed Orchard pool into the new Ironwood pool, but the system enforces a constraint: total withdrawals from the new pool cannot exceed verified deposits. This effectively neutralizes any counterfeit ZEC that might have been created through the old bug, because phantom coins can’t pass through the turnstile’s verification checks.

The migration challenge

$80 million on day one is encouraging, but it represents a fraction of the $1.7 billion to $1.89 billion that was locked in Orchard. The bulk of ZEC holders still need to actively move their funds.

Unlike most network upgrades that happen invisibly in the background, Ironwood requires users to take deliberate action. If you held shielded ZEC in the Orchard pool and you want to keep using Zcash’s privacy features, you need to migrate.

Market reaction and price dynamics

ZEC traded between $463 and $500 around the time of the upgrade activation, with daily price declines ranging from 5% to 8%.

For existing holders, the immediate calculus is straightforward. Migrating to Ironwood is essentially mandatory if you want to continue using shielded transactions. The old Orchard pool is sealed. Funds sitting there aren’t lost, but they’re in a pool that the network has explicitly marked as compromised.