Circle will begin reducing limits on its legacy Cross-Chain Transfer Protocol (CCTP) V1 starting October 31, 2026, with a full pause of the service scheduled for December 1. The change requires developers and applications to update their integrations to maintain USDC cross-chain transfers. The replacement protocol uses separate smart contracts and is not backward compatible with CCTP V1, meaning existing integrations must be migrated rather than simply updated in place. Circle has urged app developers to transition ahead of the December deadline to avoid disruption to USDC transfer functionality across chains.