Due dates for GSTR-3B returns established, with specified jurisdictional extensions and mandatory electronic payment timing. Prescribes that FORM GSTR-3B returns for July 2018-March 2019 are to be furnished electronically through the common portal generally by the twentieth day of the succeeding month, subject to specified provisos extending or altering deadlines for certain months and specified jurisdictions; taxpayers newly allotted GSTINs for a transitional filing period are required to furnish returns by a consolidated final date; and tax liabilities shown in the return must be discharged by debiting the electronic cash ledger or electronic credit ledger no later than the last date for furnishing the return.