[Standard] Sei - Pacific and Atlantic - Upgrade to v6.6.3

Scheduled for Sep 3, 00:00 - 04:00 UTC

Scheduled

We are upgrading our Sei Pacific and Atlantic infrastructure to seid v6.6.3.

This is a patch release with no state-machine or consensus-breaking changes, recommended for RPC operators and validators. It includes a memory leak fix in snapshot writes, improved snapshot durability and validation, new freeze mode for historical EVM RPC, a frozen RPC router for block-scoped request fanout, and hardening fixes for nested block reference parsing and JSON-RPC batch handling. During the maintenance window, brief interruptions to RPC availability may occur.

RPC Changes:
- EIP-1898 block references — Nested block reference parsing depth is now capped at 16 levels to prevent quadratic parse time and protect against adversarial inputs.
- JSON-RPC batches — Router batch allocations are now bounded with write timeouts to prevent unbounded memory allocation from slow clients.
- Freeze mode — Historical EVM RPC nodes can now be held at an upgrade boundary via freeze mode, continuing to serve state while staying out of mempool gossip; the frozen RPC router fans block-scoped requests to the matching frozen node.

https://github.com/sei-protocol/sei-chain/releases/tag/v6.6.3
Posted Aug 28, 2026 - 19:59 UTC
This scheduled maintenance affects: SEI (Pacific-1 Mainnet — EVM JSON-RPC API, Atlantic-2 Testnet — EVM JSON-RPC API).