Not finding Softdevice_handler.h in nRF52_SDK_15.0.3

I am trying to add "Softdevice_handler" to project under nRF52 SDK_15.0.3

But i couldn't find "Softdevice_handler" in nRF SDK_15.0.3 and it is there in SDK 11

How to add Softdevice_handler from nRF52_SDK_15.0.3

Kindly provide any suggestion