Is there any change in hough circle detection from opencv 2 to opencv 4?

Hi all,
I am upgrading the OpenCV 4 from OpenCV 2. I observed that the results of though circle detection are different in both versions. Opencv 2 provides better results than opencv 4. Does anyone have any idea about it?

GaussianBlur( src_gray, src_gray, cv::Size(9,9), 2, 2);
std::vector<cv::Vec3f> houghDetectedCircles;
      HoughCircles( src_gray, houghDetectedCircles, cv::HOUGH_GRADIENT, 1, min_dist, 50, 40, 10, 60 );