changes to 3d physics in 5.6?

In my project I was using spring joints to drag rigidbodies but this no longer works after I upgraded to 5.6. I can’t move the rigidbodies at all.

I’ve looked through the release notes and not found anything obvious that’s changed. Perhaps it’s something I’ve missed?

Figured it out, it was the anchor position that was different. I’m now resetting it via script.