GSTR-1 filing restriction: failure to file GSTR-3B bars furnishing outward supply details and use of invoice facility. The amendment adds a filing eligibility condition barring a registered person from furnishing outward supply details in FORM GSTR-1 if the person has not furnished FORM GSTR-3B for the preceding two months; analogous bars apply to quarterly filers and to persons restricted in use of the electronic credit ledger, including prohibition on using the invoice furnishing facility where FORM GSTR-3B for the preceding tax period has not been furnished.