Cobo will Support the Zcash (ZEC) Ironwood (NU6.3) Network Upgrade
July 27, 2026
Dear Cobo Users,
Cobo will support the Zcash (ZEC) Ironwood (NU6.3) network upgrade.
According to the official Zcash upgrade schedule, the network upgrade will be activated at block height 3,428,143, which is expected to occur on 28 July 2026. The actual activation time may vary depending on block production.
To ensure the security of customer assets and the stability of our services, Cobo will suspend ZEC deposit and withdrawal services starting at 12:00 (UTC+8) on 28 July 2026. Deposit and withdrawal services will be resumed once the network upgrade has been completed and the network has been verified to be stable. A separate announcement will be made when services are restored.
Customer Action Required
If your organisation operates its own Zcash node, constructs or signs ZEC transactions, or relies on Zcash SDKs, RPC interfaces, or third-party infrastructure, please complete the following compatibility checks before the network upgrade:
Update the Consensus Branch ID to 0x37A5165B.
If you operate your own node, upgrade to a version that supports NU6.3, such as Zebra 6.0.0 or a later compatible release.
Ensure that your SDKs, wallet components, and any third-party services have been updated to support NU6.3.
Continuing to use the previous Consensus Branch ID or components that do not support NU6.3 may result in transaction signing failures, broadcast failures, or transactions being rejected by the Zcash network.
Important Notes
During the suspension period, please do not deposit ZEC to your Cobo deposit addresses. We also recommend that you temporarily suspend ZEC-related deposit, withdrawal, and other associated services on your side to avoid delayed deposits or other processing issues.
Once the network upgrade has been completed and compatibility has been fully verified, Cobo will resume ZEC deposit and withdrawal services. The exact restoration time will be announced separately.
References
Zcash Foundation – Zebra 6.0.0 Release: NU6.3 "Ironwood" Mainnet Activation
https://forum.zcashcommunity.com/t/zebra-6-0-0-release/56607
Zcash ZIP 258 – Deployment of the NU6.3 Network Upgrade
https://github.com/zcash/zips/blob/main/zips/zip-0258.md
Thank you for your understanding and continued support. If you have any questions, please feel free to contact us.
Cobo Support
27 July 2026
