Most major tax providers keep prior-year software available on their websites, usually buried in the "Resources" or "Prior Year Returns" section.

The service went dark on April 17, 2018—the day after Tax Day—with no forwarding address.

You cannot file your 2018 taxes using the wwwxx app today. Even if the server miraculously booted up, the IRS no longer accepts e-filing for tax year 2018 (the deadline for that refund passed in April 2022).