If you were assessed a penalty you would get a letter from the IRS. If Turbotax calculated an estimated penalty, that will be on form 2210 in your tax return package from 2024.
The general formula has not changed, although it uses a variable interest rate. The penalty is, roughly speaking, 1/2% per month of the amount owed, calculated from the date it was owed, plus about 1/2% per month interest on the entire amount owed, not just the penalty.
