Unfortunately, only one year of tax software is loaded in the IRS at any given time. 2021 is the current tax year. And that is the only year that can be electronically transmitted. If you can find a copy 2016 Turbo tax to plug your info into, you can print out your 1040 etc and mail it in. Or go on IRS.gov, IRSFORMS.gov and into PRIOR Years and find all of the forms you need from 2016. Good Luck.