However, as per Circular 9/2015 [F.NO.312/22/2015-OT], Dated 9-6-2015, you are allowed file ITRs for past six years after following the procedure laid down in that circular provided you are entitled to claim any income tax refund or are entitled to carry forward any loss. So in case you are entitled to claim refund or have any loss to carry forward, you can avail this opportunity file old ITRs also.