Users who have deposited BTC into the Stacks Wallet to pay for transaction fees can withdraw any remaining amounts by downloading and installing version v3.1.1.
This version comes with a new feature within "Settings" under "Withdraw BTC" that empowers you to enter a BTC receive for receipt of all remaining BTC in another wallet.
Important note: This version of the wallet does not operate correctly for any other purpose such as checking your balance or transaction history, which has been frozen since January 2021 on Stacks 1.0 upon the launch of Stacks 2.0. Please do not use it for any purpose other than withdrawing BTC.
Note that BTC is no longer be needed for paying such fees on Stacks 2.0. Download the new Stacks Wallet to send STX.