GSTR-3B filing deadlines: returns for the stated months must be filed electronically by prescribed monthly due dates. Under sub-rule (5) of rule 61 of the Tripura State Goods and Services Rules, 2017 read with section 168 of the Tripura State Goods and Services Act, 2017, the Chief Commissioner, on Council recommendation, specifies that FORM GSTR-3B shall be furnished electronically through the common portal by the due dates set out in the Table for the listed months; the notification is effective from the date of issuance.