Furnishing inward supplies: registered persons must electronically report and rectify inward-supply details within prescribed timelines and conditions. Registered persons (excluding Input Service Distributors, non-resident taxable persons and specified taxpayers) must verify supplier-provided outward-supply data to prepare inward-supply records and may include undeclared inward supplies. They must electronically furnish inward-supply details, including reverse-charge and integrated-taxable supplies and related credit/debit notes, between the eleventh and fifteenth day of the month following the tax period, subject to prescribed form, manner and any Commissionerial extension. Recipients' modifications must be communicated to suppliers; unmatched entries must be rectified with tax and interest in the period of discovery, but not after the September monthly return following the financial year or the annual return, whichever is earlier.