Circle sets Dec. 1 cutoff for legacy USDC cross-chain contracts

The change affects integrations rather than the ownership of USDC. Circle says pending redemptions will remain available during the wind-down and that it will maintain enough minting capacity to process outstanding attestations before V1 is fully paused. Applications that continue routing through the old contracts after the cutoff will stop transferring USDC crosschain.

A breaking migration for developers

CCTP V2 is now called CCTP and uses separate contract addresses, interfaces and APIs. Circle's migration documentation says integrators must update the TokenMessenger, MessageTransmitter and TokenMinter contracts, change `depositForBurn` calls and replace the legacy message flow with the V2 messages endpoint.

The upgrade also changes how transfers are selected and priced. V2 adds standard and fast transfer modes, hooks and fees for fast transfers, while the current supported-chain matrix lists Noble and Sui as V1 (Legacy)-only networks. The migration therefore requires application testing around contract addresses, route availability, finality settings and any chains that do not yet have a V2 path.

The exposure is not yet named

Independent reports from CryptoSlate and Crypto Economy describe the same 95-day implementation window and note that Circle has not identified the exchanges, bridges, wallets or applications still calling V1. That leaves the number of production integrations at risk undisclosed, even though the technical deadline is now fixed.