From October 2019 onwards, FORM GST ANX-1 will be made compulsory. Large taxpayers (having aggregate turnover of more than Rs5 crore in previous year) have to file FORM GST ANX-1 on monthly basis whereas small taxpayers may file first FORM GST ANX-1 for the October-December 2019 quarter in January 2020.
For October and November 2019, large taxpayers will continue to file FORM GSTR-3B on monthly basis and will file first FORM GST RET-01 for December 2019 in January, 2020.
From October 2019, small taxpayers will stop filing FORM GSTR-3B and start filing FORM GST PMT-08. They will file their first FORM GST-RET-01 for the October-December 2019 quarter in January 2020.
From January 2020 onwards, FORM GSTR-3B will be completely phased out.