Sei Mainnet is undergoing a network upgrade to v6.6.0. This is a mandatory, governance-approved upgrade (Proposal #122) that will activate automatically at block height 224201091, targeted for approximately August 4, 2026 at 16:30 UTC. Expected downtime during the transition is a few minutes. During the maintenance window, brief interruptions to RPC availability may occur.
RPC Changes: - Transaction receipts now correctly report the EIP-1559 effective gas price, resolving prior inconsistencies for users relying on this field. - eth_feeHistory responses now include the projected next-block base fee. - eth_blobBaseFee is now exposed on the RPC surface. - Several RPC methods (including eth_getBlockTransactionCountByHash, eth_getBlockTransactionCountByNumber, eth_getFilterLogs, eth_getFilterChanges, eth_getTransactionByBlock*AndIndex, and eth_getTransactionReceipt) now return more consistent, spec-compliant results in edge cases, such as returning null or an empty array instead of an error or inconsistent value. - JSON-RPC batch request handling is now more spec-compliant, including handling of null and non-standard request IDs. - Legacy Sei-specific RPC endpoints are now deprecated.