IRAY IOR and Scattering parameter in refraction tab issue.

[Juwon5D64]

I'm trying to render transpatent plastic material.

So I'd like to put plastic IOR value in IRAY render

But IOR parameter is stuck within 0~1 range and can't put value over it.

also in the past I remeber I could access Scatter value in this refraction tab.

but this parameter is missing, gone.

Is it because I made wrong set up or is it issue of this new update?

I double checked It's PBR-Metal-Rough-with-alpha-Blending shader.