Depending on what your tax situation was last year, you might need to use new tax forms to claim the same deductions, credits, or forms of income. Some of these situations are now in TurboTax Deluxe and TurboTax Live Deluxe, instead of in Free. Also, if you have certain tax situations such as a mortgage, charitable donations, medical expenses, or student loan interest deduction, these also require Deluxe.
Here is more information about why you may need to upgrade from Free Edition. https://ttlc.intuit.com/replies/4223394