Return filing deadline: FORM GSTR-3B November filing required electronically by 23 December, effective from 20 December. The amendment inserts a proviso requiring the FORM GSTR-3B return for November 2019 to be furnished electronically through the common portal on or before 23rd December, 2019, and states the amendment is deemed to have come into force from 20th December, making the revised filing deadline operative for discharge of the November 2019 tax liability.