As stated above, the online software is for 2018 only. If you had started a 2017 return using the online software, here are the instructions for completing that return. It will have to be filed by mail no matter where or how you prepare it.
How
do I finish a prior-year return that I started in TurboTax Online?
And if you have not started the 2017 return, but need to file it, you can use the desktop software (2017 version). Here is a link to prior year products. File
past years' taxes for 2017
