It's not mandatory as per the notification issued earlier at time of Quarterly filing of GSTR 4.
but now, GSTR 4 made annually and for annual return there is no separate clarification/exemption till date.
So as on date it's mandatory to disclose the Purchase /inward Supplies details in your ANNUAL FORM GSTR-4 for F.Y 2019-20 having last date 31st August, 2020
CAclubindia
