I found this in the Litchi manual at
Help - Litchi:
Collision Avoidance: Enables/disables collision avoidance. Mavic/Phantom 4/Inspire 2/
Spark only.
Active Obstacle Avoidance: Enables/disables active obstacle avoidance. When enabled, and an obstacle is moving towards the aircraft, the aircraft will actively fly away from it. If while actively avoiding a moving obstacle, the aircraft detects another obstacle in its avoidance path, it will stop. Collision Avoidance must also be enabled. Mavic/Phantom 4 (Advanced/Pro/ProV2)/Inspire 2/
Spark only. iOS only.
I have not actually tried these "features" so don't know if they work.