if you have only the xxx.tax201X files, those can only be opened by that year's app which is no longer available.
if you need them quickly, there is a service that you can e-mail the files to and you get back PDFs of the returns, this company is not affiliated with Turbotax. Use at your own risk
https://www.taxprinter.com/
if you can wait, you can file form 4506 with the iRS to get copies of the return. there is a fee of $30/return
https://www.irs.gov/pub/irs-pdf/f4506.pdf
or you can request a transcript of the return using either
1) form 4506-T by mail
https://www.irs.gov/pub/irs-pdf/f4506.pdf
2) or download a copy by registering or accessing your account if already registered.
https://sa.www4.irs.gov/sso/?resumePath=%2Fas%2FfSVDhY4ETc%2Fresume%2Fas%2Fauthorization.ping&allowI...
