[DigitalToday reporter Yoonseo Lee (이윤서)] Zcash will apply the 'Ironwood' network upgrade on July 28 local time at block height 3,428,143.

According to blockchain media outlet U.Today, the upgrade is designed so all users can independently verify the integrity of Zcash (ZEC) circulating supply.

The upgrade is slated as version NU6.3. It is set to take effect around noon UTC on the 28th. The key change is to effectively end the existing Orchard shielded pool and introduce a new shielded pool that reflects a modified Orchard circuit. It also keeps the turnstile mechanism to prevent more ZEC from leaving than legitimately entered the existing pool.

Zcash Open Development Lab (ZODL) said in an X post on the 26th that mainnet activation is two days away. It added, "There is no need to give up privacy verifiability," and said, "Ironwood guarantees both."

The move follows a major counterfeiting vulnerability found in the Orchard shielded pool. Shielded Labs security researcher Taylor Hornby found the vulnerability, and ZODL later led an emergency network upgrade to fix the issue. ZODL viewed the likelihood of actual exploitation as low.

But transaction data in the existing Orchard is shielded, making it difficult for users to independently confirm that no counterfeit ZEC was created before the vulnerability was fixed. Ironwood targets this by sealing the existing Orchard pool and switching to a new pool that applies the modified circuit. After that, anyone running a node will be able to verify whether the supply limit is being properly enforced.

After the upgrade, the ability to send or receive ZEC within the Orchard pool will be halted. Funds will be able to exit only through Zcash's existing turnstile. Zcash explained that the structure is intended to prevent hypothetical counterfeit amounts from increasing circulating supply.

That is also why market participants are watching the upgrade. It changes the structure so external verification of supply reliability is possible while maintaining privacy features. In particular, since the prior vulnerability was in the Orchard pool, once the network transition is complete Zcash will focus on reducing uncertainty over supply integrity.

Still, the transition process leaves the possibility of service disruptions. Users need to be cautious because deposits and withdrawals or some functions may be temporarily suspended if exchanges, wallets and other service providers do not complete upgrade preparations.

The core of Ironwood is that it increases supply verifiability while maintaining privacy features. Zcash sealed the existing Orchard pool and switched to a new shielded pool, adjusting both its response to the security vulnerability and the structure for controlling circulating supply.

Zcash to Activate Ironwood Upgrade With New Shielded Pool and Supply Safeguards Zcash is expected to activate its Ironwood network upgrade at block height 3,428,143 on July 28. The upgrade introduces a new shielded pool with quantum-recoverable notes and a turnstile mechanism… pic.twitter.com/CuFQ0RMAmt