Aggregate turnover threshold triggers quarterly GSTR 1 filing requirement for small taxpayers, with quarterly deadline set and monthly limits to follow. Notifies registered persons with aggregate turnover up to the small taxpayer threshold in the preceding or current financial year as a class required to follow a special procedure and to furnish details of outward supplies of goods or services in FORM GSTR-1 for the specified quarter, with the quarter's final filing date prescribed and time limits for related monthly returns to be notified subsequently in the Official Gazette.