GST Circular No 144/2020

CBIC waived recording of UIN on invoices pertaining to refund claim from Apr 20 to Mar 21, subject to the condition that copies of such invoices are attested
by the authorized representative of such UIN entity and submitted to the jurisdictional officer

This waiver was available till Mar 20, however with circular 144/14/2020 it is further extended to Mar 21

Recording of UIN on invoices does not impact liability of supplier but would have enabled recipient i.e. Foreign Diplomatic Missions/Consulates/UN Organizations to claim refund of the taxes paid by them