As per the latest announcement, GSTR-3B should be filed till the month of December. GSTR-3B for July should be filed by 25th August or by 28th August, if you’re planning to file TRAN-1 for July.
The GSTR-3B for the month of August should be filed by 20th September.
The filing due dates for the remaining months have not been announced yet.
Note: The introduction of the GSTR-3B does not eliminate the need to file the GSTR-1, GSTR-2, and GSTR-3 for the respective months.
and GST filing.