Gstr 2 to gstr 1a - what is reflect in sellers end...???

Any invoices add , modified or rejected by the buyer so these will be refected in gstr 1a of supplier return but as the gstr 2 due date is extended to 30-11-2017 so it will refected after that and you can only able to file gstr 1a after gstr 2 , not earlier then this . . . 

if your buyer (counter party) filed th gstr 2 then it will be refected in gstr 1a of your , if not then this is sytem error .