Well its been 3 years for a posted suggestion and we have some work arounds, but it would be nice to have a device like the Sonoff SV to have an added with input for external switch. I believe the hardware is their to support it as I can see on the silkscreen on the PCB of The SV has a unpopulated connector marked for IO14, IO 4, and IO5 , we just need a software and app update.
Can wee please get this update! Please click vote to get this done.