CryptoSlate posted that USDC runs across 37 mainnets. Circle cannot upgrade every wallet, bridge or host chain itself. Post-quantum migration requires each layer to rotate keys and retire vulnerable signatures. The 813 logical-qubit figure shows progress in attack design, not a Q-day deadline. The linked article states USDC may be only as quantum-safe as its slowest wallet, bridge or blockchain. Quantum migration requires 37 host networks, wallets, custodians and bridges to coordinate beyond Circle’s own post-quantum upgrades.