Some features are incompatible with multithreading and reliable evaluation
of dependencies. We are now removing them as part of a bigger cleanup to
fix bugs in keyframing and invalid animation evaluations.
- Dupliframes have been removed. This was a hack added before there were more powerful features like the array modifier.
- Slow parent has been removed, never worked in 2.8. It was always unreliable for use in production due to depending on whatever frame was previously evaluated, which was not always the previous frame.
- Particle instanced objects used to have their transform evaluated at the particle time. Now it always gets the current time transform.
- Boids can no longer do predictive avoidance of force field objects, but still for other particles.