This discussion clarifies whether it's possible to amend bills from FY 19-20 in GSTR 1. According to Section 39(9) of the CGST Act 2017, the deadline for amending GSTR 1, including corrections or omissions, was the due date for furnishing the return for September 2020. Therefore, amendments for FY 19-20 are no longer permitted as the time limit for issuing credit or debit notes has passed.
As per section 39(9) of the CGST act 2017 ,last date to amend GSTR1 for any correction omissions was ,due date of furshing return for the month of September 2020 .