[Urgent] Zcash - Mainnet &Testnet - Zebra 6.2.1

Scheduled Maintenance Report for Quicknode

Completed

The scheduled maintenance has been completed.
Posted Jul 27, 2026 - 15:00 UTC

In progress

Scheduled maintenance is currently in progress. We will provide updates as necessary.
Posted Jul 27, 2026 - 11:00 UTC

Scheduled

We are upgrading our Zcash Mainnet infrastructure to Zebra v6.2.1.
This is a security and bug-fix patch release that mitigates a peer-driven CPU-exhaustion vector affecting nodes with NU6.3 (Ironwood) active by rejecting underpaying and structurally invalid shielded mempool transactions before expensive proof verification, and disconnecting peers that send transactions with invalid shielded proofs.
The release also improves chain synchronization retry logic.

During the maintenance window, brief interruptions to RPC availability may occur.


RPC Changes:
getblocktemplate — On Testnet, minimum-difficulty block template switching has been corrected to occur only when consensus threshold is reached, rather than up to 150 seconds early; this prevents spurious minimum-difficulty blocks that artificially depress difficulty.

Release: https://github.com/ZcashFoundation/zebra/releases/tag/v6.2.1
Posted Jul 23, 2026 - 14:33 UTC
This scheduled maintenance affected: Zcash (Zcash Mainnet - JSON RPC API, Zcash Testnet - JSON RPC API).