GSTR1 filing later fee?

Currently 200 per day.

Notification of Rs. 50/20 per day applies to GST 3B Only as per notification 64/2017 of CGST Act

Maximum 5000/- 

Maximum Penality is Rs. 10000 (5000 each as per Section 47 of CGST ACT and SGST Act).

Late Fees for GST Return as per GST Act

• All returns except Annual Returns: Rs. 100 per day (Rs. 50 CGST + Rs. 50 SGST) of default up to a maximum of Rs 5,000.
• Annual Returns: Rs. 100 per day (Rs. 50 CGST + Rs. 50 SGST) of default up to a maximum of 0.25% of Turnover.