I just received this warning from Bittrex regarding Bitcoin Gold
As a valued Bittrex customer, we wanted to inform you that on November 5, 2018, we are retiring wallets that do not have markets, including Bitshares (BTS), Bitcoin Gold (BTG), and Bitcoin Private (BTCP). Our records indicate that you have a balance for at least one of the wallets being retired.
To keep your BTS, BTG or BTCP assets, you must withdraw your balance before Monday, November 5, 2018. After this date, your assets will be unrecoverable.