A new leaked document from the FCC (Federal Communications Commission) could show a dual-SIM Sony Xperia Z4. If this it’s true it will be the second smartphone by Sony to have two SIM cards, the previous was the Sony Xperia Z3 Dual.
The listing refers to a model with the number PM-0851-BV with dual-SIM capabilities. According to this FCC document the only hardware difference is in the second SIM socket.
Probably, for more informations about this device we will have to wait for the Mobile World Congress a little over a month from now.