Collision point problem

I would like to check vector2d for collision point.
In 2018 my code is working good:

void OnCollisionEnter2D (Collision2D col)
  print("First point that collided: " + col.GetContact(0).point);

but when I export my project to Unity 2017 this code is not working.
There is a bug:
IndexOutOfRangeException: Array index is out of range.
and I dont know why.

How can I check collision2d point in Unity 2017?

Thank you
This works:

  print("First point that collided: " + col.contacts[0].point);

using System;