Purpose: a short operational guide for Threshold Committee members. This only includes what to do, why each call exists, the calldata, and how to verify the result.

Summary

The Council Safe upgrades tBTC from the old canonical vault to the new instant-swap-aware vault, tells the Bridge to trust that new vault, and grants the instant minter signer permission to mint through the new vault.

Is This A Timelock Operation?

• No OpenZeppelin TimelockController.schedule() or execute() call is used.
• There is still a required delay: TBTCVault.GOVERNANCE_DELAY() = 86400 seconds between Session 1 and Session 2.

Tenderly vNet Used For This Check

• Dashboard: https://dashboard.tenderly.co/explorer/vnet/e5764198-a494-4fc3-afeb-aaed51b033e6/transactions?perPage=20&page=1
• Cast readbacks: PASS

Required Actions

Session 1: Start The Upgrade Clock

Why: this records the new vault address in the old vault and starts the 24-hour delay. It does not move tBTC ownership yet and does not change Bridge trust yet.

from Safe: 0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f
to:        0x9C070027cdC9dc8F82416B2e5314E11DFb4FE3CD
value:     0
function:  initiateUpgrade(address)
argument:  0x6fbE36CA2c7DCf4b739572eeEB70a40f31E2131d
calldata:  0x479aa9270000000000000000000000006fbe36ca2c7dcf4b739572eeeb70a40f31e2131d

Tenderly vNet proof:

tx id:   d8b3526e-4c25-4fcb-93c1-ce8573265d6a
tx hash: 0xc2cd92d26b52324c79469e88018defcc0333afa4381eb11ac6ce33585082e415
status:  success
gas:     69,637

Wait at least 86400 seconds after Session 1 before Session 2.

Session 2: Finalize, Trust, Grant Minter

These three calls should be submitted as one Safe batch in this exact order.

2a. Finalize Old Vault Upgrade

Why: this moves tBTC token ownership and the old vault Bank balance to the new vault, then clears the pending upgrade state.