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End of Life

⚠️ zcashd has reached its End of Life

zcashd is deprecated and does not support NU6.3. Its automatic End-of-Support halt was reached on July 18th 2026 at block height 3417100, and every zcashd 6.20.0 node has now automatically shut down and will refuse to restart. If you have not migrated yet, do so now: move to Zebra if you do not need the zcashd wallet, or to Zallet — migrating your wallet.dat — if you do.

Two key dates: End-of-Support halt vs. NU6.3 activation

zcashd’s End of Life involves two distinct milestones. Don’t conflate them:

  • zcashd End-of-Support halt — reached July 18th 2026, at block height 3417100. The point at which every zcashd 6.20.0 binary automatically shuts down and refuses to restart. This is hard-coded as the deprecation height (DEPRECATION_HEIGHT in src/deprecation.h). The chain reached this height on 2026-07-18, so all zcashd 6.20.0 nodes have now halted. See Release Support for more on the End-of-Support halt.
  • NU6.3 mainnet activation — estimated July 28th 2026. The Ironwood/NU6.3 network upgrade activates on mainnet a few days after the End-of-Support halt. The halt was deliberately targeted to precede activation so that every un-upgraded zcashd node had already shut down and the network is Zebra-only before NU6.3 takes effect. zcashd does not support NU6.3.

Context

Zcash organizations continue to work on the different components that are needed to specify, develop and deploy the Ironwood shielded pool in the next Network Upgrade, NU6.3. zcashd maintainers do NOT support this upgrade. zcashd is deprecated and has reached end of life ahead of the activation of NU6.3 on mainnet.

The decision to accelerate zcashd deprecation is specifically related to the recent Orchard vulnerability disclosed on June 1st 2026 and the associated risks that the C++ codebase poses for future (or present) AI advancements. Deprecating zcashd is a mandatory step to conclude the remediation of the reported Orchard bug.

Timeline

NU6.3 activation was integrated into testnet code around July 2nd 2026, and testnet activation followed on July 4th (block height 4134000). The same followed for mainnet on later dates (see timeline below).

With regards to mainnet, zcashd 6.20.0’s automatic End-of-Support halt (block height 3417100) was reached on July 18th 2026. This precedes NU6.3 mainnet activation on July 28th, ensuring a Zebra-only network before the upgrade takes effect.

DateEvent
July 2nd 2026Ironwood/NU6.3 Testnet deployment
July 4th 2026Ironwood/NU6.3 Testnet Activation (block height 4134000)
July 9th 2026Ironwood/NU6.3 Mainnet deployment
July 18th 2026 (reached)zcashd End-of-Support halt (block height 3417100)
~July 28th 2026Ironwood/NU6.3 Mainnet Activation

The Path Forward: Zebra + Zallet

The Zcash Foundation has developed and maintains the Zebra full node, a Rust implementation of the Zcash protocol. All zcashd users that don’t need the zcashd wallet should migrate to Zebra immediately.

For those who do depend on the zcashd wallet, ZODL developers have released Zallet Alpha.4, which allows migration of zcashd’s wallet.dat files into Zallet. You can find the documentation for Zallet here. Because zcashd has now halted, these users should migrate their wallet.dat to Zallet as soon as possible and send feedback to its maintainers.