[Standard] Zcash Mainnet - Upgrade to Zebra 6.4.0

Scheduled for Oct 1, 00:00 UTC  -  Oct 2, 00:00 UTC

Scheduled

We are upgrading our Zcash Mainnet infrastructure to Zebra 6.4.0 on 2026-10-01. This release improves block template performance through precomputation, and includes multiple security and stability fixes.

Brief interruptions to RPC availability may occur on that date.

RPC Changes:
- getblocktemplate — Now uses precomputed block templates for the current chain tip when available, refreshed on tip changes and periodically, reducing latency for miners; templates may be a few seconds behind the mempool but are validated against the committed tip.
- getstandardfee — Reports updated conventional fee of 1000 zatoshis per ZIP-317 logical action (down from 5000; 2000 instead of 10000 for a minimal transaction).
- z_gettreestate — No longer returns null commitments for blocks moved to a side chain during concurrent reorgs.
- RPC response body size — `rpc.max_response_body_size` is now capped at 4,294,967,295 bytes; larger configured values are rejected during configuration loading.

https://github.com/ZcashFoundation/zebra/releases/tag/v6.4.0
Posted Sep 23, 2026 - 19:20 UTC
This scheduled maintenance affects: Zcash (Zcash Mainnet - JSON RPC API, Zcash Testnet - JSON RPC API).