Return substitution allowed: taxpayers who filed GSTR-3B need not file GSTR-1 or CMP-08 for the year. The amendment inserts a proviso providing that taxpayers who furnished FORM GSTR-3B instead of FORM GST CMP-08 for tax periods in the financial year 2019-20 are not required to furnish FORM GSTR-1 or FORM GST CMP-08 for all tax periods in that financial year.