TurboTax has software for 2018 onward. Software is no longer available from TurboTax for earlier years, nor would it be supported even if you find it on eBay, etc. Updates are not available. It is also too late to receive a tax refund for a tax year earlier than 2018---those refunds have been forfeited. BUT if you owe tax due you still have to pay with penalties and interest. There might be other software providers that have software for those years, but you will not receive refunds for the returns even if the forms show a refund.
https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
PRIOR YEAR FORMS FROM IRS
2016
Form 1040 https://www.irs.gov/pub/irs-prior/f1040--2016.pdf
Form 1040 Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
Form 1040A https://www.irs.gov/pub/irs-pdf/f1040a.pdf
Form 1040AInstructions https://www.irs.gov/pub/irs-prior/i1040a--2016.pdf
Form1040EZ https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
Form 1040EZ Instructions https://www.irs.gov/pub/irs-pdf/i1040ez.pdf
**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.**
