The Base mainnet will undergo the Optimism Superchain U16A upgrade on October 8

ChainCatcher message, Base Build announced on platform X that the Base mainnet will undergo the Optimism Superchain U16A upgrade from 1:00 to 3:00 Beijing time on October 8.

This upgrade will temporarily invalidate pending withdrawals from the Base mainnet to Ethereum L1. Deposits and on-chain activities will continue as normal, and this invalidation will not pose any risk to any ETH or ERC-20 tokens.

The official reminder for users is to ensure that all pending withdrawals are completed before 17:00 UTC on October 7, 2025. Any incomplete withdrawals will need to be re-validated after the upgrade is completed.