What is the best way to file past returns for the years 2014, 2015, 2016 and 2017? I understand TurboTax has desktop versions for 2017 and onward.

[TurboTaxSusan]

As you mentioned, we have TurboTax Download/Desktop (for Windows) for 2017. You can use this to NETFILE or print and mail your 2017 return. You can find it under the 2017 tab here: https://turbotax.intuit.ca/tax/software/prior-year-taxes

We no longer have any TurboTax products available for tax years 2016 or earlier. However, you can still download the forms for those years from the Canada Revenue Agency (CRA) here: https://www.canada.ca/en/revenue-agency/services/forms-publications/tax-packages-years.html

NETFILE is no longer available for 2016 or earlier, so you would need to print and mail your returns.