Thanks to valued customer feedback and suggestions,  King Pigeon R&D engineers team improve product a lot.  
Industrial cellular router R40 has added the following functions.

(1)  MQTT subscription :  Add a new mode , only the changed data is transmited by MQTT 
(2)  Dual-SIMs:  Add an enable switch to power off any one of the cellular module when necessary
(3)  MQTT : support custom  data format
(4)  Modbus setting:  people can configue the acquision cycle and response timeout time on Modbus master station  
(5)  The cycle timer :   people can configue the start time and end time ,  the number of cycles 
(6)  Ethernet ports new feature:   WAN port can switch to LAN port  in network settings
(7)  USB port new feature :  when a U disk or mobile hard disk is connected to the USB port of the R40 router,   internet computer can access this storage device by the mean of accessing network shared directory

R40 product page