GST compliance extensions permit use of credit notes, refund vouchers and deferred filing to ease taxpayer obligations. Suppliers who received advances for cancelled supplies must either issue a credit note (when invoiced) and adjust liabilities in returns, or issue a refund voucher (when no invoice) and claim refund via FORM GST RFD-01; goods returned after invoicing require credit notes and return adjustment. Letter of Undertaking requirements for zero-rated supplies are temporarily extended permitting continued supplies under prior-year LUT subject to filing FORM GST RFD-11 within the extended period. Deposits of TDS and filing of GSTR-7 and refund application deadlines falling in the affected period are likewise extended.