Base Mainnet will be undergoing the @Optimism Superchain U16A upgrade on October 2, 2025 between 17:00-19:00 UTC This upgrade will temporarily invalidate pending withdrawals from Base Mainnet to Ethereum L1. Deposits and onchain activity will continue as normal; this invalidation doesn't place any ETH or ERC-20 tokens at risk. Please ensure that any pending withdrawals are finalized before October 2, 2025 at 17:00 UTC. Any unfinalized withdrawals will need to be reproven after the upgrade completes.(Base Build)