Interest in case of late payment

I am trying to file GSTR 4 for the period Jan 2018 to March 2018, where the due date shows 31/3/2019. As per notification no 77/2018, the late fees has been waved off so that there is no late fees. But I am not be able to enter the interest to be payable due to such changes in the portal. Shall I need to pay interest in current period for the previous returns???