The software for 2014 is retired, so you cannot use TurboTax for 2014. Software for 2015 through 2018 is still available, although you are too late to receive a tax refund for 2014 or 2015. If you owe, you still need to pay your tax due, though, along with interest and penalties which will be calculated and billed by the IRS.
The current online software can only be used for a 2018 return. Only a 2018 return can be e-filed. Earlier years must be printed and mailed. Mail them in separate envelopes.
To file a return for a prior tax year
If you need to prepare a return for 2015, 2016, or 2017 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
