Nothing changes. But I would expect you to get two 1098-Mortgage Interest Statements for 2021. One for the old loan, and another for the new loan. Enter the one for the old loan first. Then when you enter the 2nd one, on one of the screens will be a selection you make to indicate that the 2nd loan is a refi. You'll need to deal with you're refi fees then.
If you refinanced with the same lender, then the remaining loan acquisition fees on the old loan are added to the loan acquisition fees for the new loan and that total is amortized and deducted over the life of the new loan.
If you refinanced with a different lender, the remaining fees on the old loan to be deducted, are fully deductible in the year of the refinance.
