TTX online shuts down for the 2016 tax filing season on Oct 16 at midnight pacific time. So don't bother with it. Since you have to use the CD/Desktop version to file a prior year's return anyway, you might as well go ahead and purchase the desktop version for 2016 too. I assume you already know to file the oldest tax return first, and that you should mail each tax return in a physically separate envelope to the IRS.
