Gravity Collider works in 4.0+!
(Tested working perfect in 4.2 as well)

Here's a part 2 tutorial showcasing a few more things!

Youtube vid: https://www.youtube.com/watch?v=2OAROGQ-vsM

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Gravity Collider makes adding bone physics easy in simply 2 clicks! Skirts, hair, armor jiggling, breasts, key-chains, all kinds of stuff gets basic physics using boxes set up in a bead necklace formation. The collision boxes are quickly adjustable whenever or however you want and weight painting them is painless and powerful.
Extremely light, scales with the model, and even exports to game engines perfectly. On top of all this, because it uses ik, you can gradually turn off the physics for full control at any moment you need and gradually turn them back on again. No need for a perfect run, just go animate!

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Tips:
. The menu will show in bone edit mode
. Make sure to apply GC when the model is in an active t-pose.
. I have reset all bones on frame zero and start animating on frame 1, but it's also easy to reset all the bones on any key after you've animated and clear it later!
. When weight painting, be careful of using Undo as Blender might switch off of the necessary "Pin" Vertex group shown in the tutorial video.
. Auto-rigs are weird. GC works well when the bone chain is simple with clean parenting
. Make sure not to have other BONE modifiers in the stack when applying GC. May cause glitchy behavior. I recommend baking the animation/modifiers if there are any.

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Now newcomers can skip so much of the painful learning process with physics and just focus on animating until they're ready for the deeper stuff. If this helps you then please help spread the message!

There is a free download on Min's Github if you'd like to check it out:

Min's GitHub: https://github.com/MiniEval/Bone-Physics

(Blender 3.6+, but DOES work in Blender 2.8 with a traceback warning that doesn't seem to effect general usage at first glance)