Hi caren.padc,
The scene file from R19 will not work in S24 since the Progressive Render is no longer part of the application.
It is possible to convert the file and have it running in Standard or Physical Render in S24, but the setup for Redshift 3d would be different. The Sky Object with the radiance should be an RS Dome Light with an OpenEXR.
(Note that a Radiance is a low-quality HDRi source, to begin with, to just save it as OpenEXR will not improve anything).
A Radiance (.hdr) file is a 4*8bit/channel file (NOT a 32bit/float per channel at all, which means that the color information is relatively limited.
The idea of this tutorial was to create a kind of a “normal” material interface with nodes under the hood. That doesn’t feel really Redshift3D like.
With some differences in the Node system (RS3D v. C4D), here is the file with Cinema 4D’s node system as a starting point.
https://www.amazon.com/clouddrive/share/qC1lFbDTxDaHAVPiwdJCGy1b4zNpmgfxsar3otYKvth
I hope you can get what you want, and enjoy the material despite all the recent changes.
All the best