This was copied from bspranger's repo (https://github.com/bspranger/Xiaomi/tree/master/devicetypes/a4refillpad/xiaomi-aqara-door-window-sensor.src) and modified to work with my specific Xiaomi Aqara Door/Window Sensors.
I don't know if they will work on others but this is what I had to do to get it to work with mine.
Everything you need to know about them and SmartThings is in this thread.
https://community.smartthings.com/t/release-xiaomi-sensors-and-button-beta/77576