Letter of Undertaking permitted instead of bond for zero-rated exports, subject to eligibility, execution and payment conditions. Specifies conditions for furnishing a Letter of Undertaking in lieu of a bond for export without payment of integrated tax: eligibility excludes persons prosecuted for offences where tax evaded exceeds the specified threshold; the LUT is to be on registrant letterhead, in duplicate, for a financial year in the annexure to FORM GST RFD-11 and executed by prescribed authorised persons; the LUT becomes invalid if tax and interest are not paid within prescribed periods and resumes validity upon payment; provisions apply mutatis mutandis to zero-rated supplies to SEZ developers or units.