E Invoice schema updates standardize invoice fields and amend registration and notice provisions under GST rules. Amendments extend specified deadlines in Rule 117, add SEZ-related registration fields in FORM REG-01, revise wording and insert a system notice statement in FORM GSTR-3A, and wholly replace FORM INV-01 with a comprehensive e invoice specification (FORM GST INV 1) that prescribes field cardinalities, mandatory and optional invoice elements, detailed supplier/buyer/item/tax/transport/payment data, and digital signature provisions.