Can anyone help provide more explanation to this message? "Why do I need to upgrade? You have Additional Medicare Tax (Form 8959)."

[BillM223]

Unless Social Security tax, which is imposed on the first $160,200 that you earn, Medicare tax has no upper limit.

To quote the IRS: 

Additional Medicare tax applies to an individual's Medicare wages that exceed a threshold amount based on the taxpayer's filing status. Employers are responsible for withholding the 0.9% Additional Medicare tax on an individual's wages paid in excess of $200,000 in a calendar year, without regard to filing status. An employer is required to begin withholding Additional Medicare tax in the pay period in which it pays wages in excess of $200,000 to an employee and continue to withhold it each pay period until the end of the calendar year.

So your employer must have paid you more than $200,000. And Form 8959 is not in the Basic product.