The last date to file the GSTR 4 return for the financial year 2019-20 was 31st October 2020. This was confirmed by notification 64 (C.T) dated 31st August 2020. As of now, no extension has been announced by CBIC.
Last date for GSTR4 for F.Y 2019-20 was 31/10/2020 as per notification 64 ( C.T) Dated 31/8/2020 , just confirm any extension on CBIC web site in notification section .