Are the Sensor Calibration Routines Working?

I noticed that the mag sensor calibration routine has not been updated for 6 months and is not in the latest release of v1.6.0.rc1. I am using v1.5.4 and am wondering if there is a significant improvement to how the values get calculated and applied? I’ve been testing a lot with internal/external magnetometers and am finding that the yaw solution is still very bad Any one else experience this?

Is there any way for me to get a version of v1.5.4 with the updated calibration routine ? I’m really interested in the commits on mag_calibration.cpp from Jan 31, 2017 and i’m willing to test the sh*t out of it.