Extension of GSTR-1 filing deadlines for small taxpayers; quarterly return due dates deferred under GST notification. Registered persons with aggregate turnover up to Rs. 1.5 crore may follow a special quarterly procedure to furnish details of outward supplies in FORM GSTR-1, with deferred due dates for specified quarters; the notification invokes section 148 of the Rajasthan Goods and Services Tax Act, 2017, supersedes an earlier departmental notification, and provides that further special procedures or extensions under section 38(2) and section 39(1) for July 2017-March 2018 will be notified subsequently.