Arbitrum approves disabling its legacy USDT bridge

What happened

Arbitrum DAO voters approved a constitutional proposal to disable the legacy USDT gateway after migration of most cross-chain activity to USDT0.

What changed

If the approved action is executed, new calls routing legacy Ethereum USDT through the specified L1 gateway would revert, retiring that deposit path and requiring integrations to use another route.

What did not change

The Snapshot approval did not execute the DisableGatewayAction. It did not deprecate the canonical bridge for other assets or establish the final state of third-party integrations.

Confirmed

• The official vote ended on July 31, 2025 with approximately 159.4 million ARB voting for the proposal.
• The target is legacy Ethereum USDT at 0xdAC17F958D2ee523a2206206994597C13D831ec7.
• The proposal specifies DisableGatewayAction contract 0x8d3425f7039645223517F6F6e60Ef04C28f4188F.
• The stated legacy route has a seven-day withdrawal delay and can create refund problems for depositing smart contracts.
• The proposal states that transactions submitted after disablement would revert.

Still open

• The subsequent Tally vote and execution transaction.
• The exact effective block and final L1GatewayRouter mapping.
• Whether every wallet, exchange, and smart-contract integration migrated before execution.
• Treatment and exit paths for existing legacy bridged USDT balances.

What it means for an advisor

• Review the Arbitrum Bridge memo's supported-asset routes and integration assumptions before treating the legacy USDT path as unavailable.
• Verify on-chain execution and existing-balance withdrawal behavior; approval alone does not retire the gateway.