It is too late to receive an income tax refund for those tax years. Any refunds have been forfeited. If you owe tax due, however, you still need to pay the tax, and then the IRS will bill you for the penalties and interest still owed.
Software is no longer available for those tax years, but you can use the paper forms to prepare the returns by hand. Or seek a local tax pro who can still do a 2017 return.
