The deadline to amend GSTR1 returns for the financial year 2019-20 has passed. According to Section 39(9) of the CGST Act 2017, the final date for corrections was the due date for the September 2020 return. Therefore, it is no longer possible to amend invoices from April 2019 or any other period within FY 2019-20.
Last month and date to correct errors in GSTR 1 for F. Y 19-20 was the date of return for the month of September 20 , as per section 39(9) of the CGST act 2017 .