I accidentally set my min shading rate at 0.00... and it actually renders. In a few minutes. With IDL and SSS enabled. (Admittedly, it's just a head render of a single figure, and my other render settings aren't particularly high. But I'm pretty sure I couldn't have done that in older versions.)

EDIT: D'oh. Nevermind about SSS. (It was on in render settings, but now that I think about it, it's not applied to any materials.) OTOH, IDL quality was 6 and pixel samples was 4, so not exactly draft quality.

Did you just set that in the render settings?  Because anything below 0.2 will be disregarded anyway since you'll have to lower it in the Properties of each element in the scene.    So, unless you changed the shading rate on the objects/figures themselves it still rendered at 0.2.

 

D'oh. Forgot about that...

Although, even getting any size of 0.2 render was difficult before, anyway.

Hm. I never thought about setting it per figure. Is there any benefits in that?

Well, if something is in the background, you don't need the quality cranked up so high, so you can steward your computing resources for what's going to make a difference.