GST return filing dates extended for Tamil Nadu, parts of Andhra Pradesh due to Cyclone Titli Updated : November 29, 2018 06:26 AM IST The deadline for filing the GSTR-3B form for October has been extended to December, 20 for eleven districts of Tamil Nadu. For all taxpayers, deadline for filing the GSTR-7 form for October to December, is extended to January 31, 2019.