GSTR-3B filing deadlines require electronic discharge of tax liabilities via cash or credit ledger by the due dates. The notification prescribes monthly filing deadlines for returns in FORM GSTR-3B for August through December 2017 to be furnished electronically through the common portal on or before the specified last dates, and requires registered persons to discharge tax liabilities by debiting the electronic cash ledger or electronic credit ledger not later than those dates, subject to Section 49 of the Act.