Turbotax no longer offers apps to do those years. you'll either have to do them manually or find a professional. they usually have the apps for those years.
if you are due refunds they are forfeit for failure to timely file those years.
on the other hand if you owe the iRS can come after you.
https://www.irs.gov/forms-pubs/prior-year
https://www.irs.gov/forms-pubs-prior-search?search=1040
