Rate of exchange for GST valuation clarified; goods use customs notified rates and services use GAAP based rates at time of supply. The amendments specify exchange rate methodology-goods to use Board notified customs exchange rates and services to use rates as per generally accepted accounting principles at the time of supply; expand export invoice endorsements to include supplies to SEZ units or developers with specified address and destination details; and empower the Commissioner to mandate electronic filing of FORM GSTR-3B through the common portal with procedures for electronic generation and reconciliation of FORM GSTR-3 and crediting excess input tax to the electronic credit ledger.