Filing obligation for newly migrated taxpayers: electronic GSTR-3B returns required by specified deadline under amended notification. The amendment mandates that taxpayers who obtained GSTIN under Notification No. 31/2018 must furnish FORM GSTR-3B electronically through the common portal for the periods July 2017 to November 2018, and that these returns be filed on or before the 31st day of December, 2018.