GSTR-3B filing deadlines adjusted for Apr-Sep 2020, with later cutoff for smaller taxpayers and payment via electronic ledgers. Specifies that FORM GSTR-3B for April-September 2020 must be filed electronically through the common portal by the twentieth day of the following month, with a later twenty-fourth-day cutoff for eligible smaller taxpayers; requires tax liabilities shown in FORM GSTR-3B to be discharged by debiting the electronic cash or electronic credit ledger and other amounts by debiting the electronic cash ledger not later than the applicable filing date.