I previously bought Wyze door sensors, will they work with the security system and how many sensors can it handle?
Welcome to our user community, @dk11 !
The old V1 contact sensors will connect to the new WHM Hub (the updated Home Monitoring replacement for the old Sense bridge that you used to plug into the back of a V2 camera). In this configuration the sensors will do everything they used to do, but they will not otherwise work with the new Home Monitoring system. For WHM functionality you will need V2 sensors.
I am not aware of a limit on the number of sensors. [thanks for filling that in below @WildBill!}
Per the detailed specs:
Up to 100