Hi Geoff,
The significant change here is that the SonicTransporter servers now have HQ Player Embedded built in. The microRendu has had the HQ Player NAA (Network Audio Adaptor) since first release.
If you do not have a SonicTransporter server, you can install HQ Player Desktop on a Windows, Mac or Linux computer. In either case I think an HQ Player licence must be purchased after the trial period in order to continue using.
HQ Player is used as a virtual endpoint with Roon and performs similar upsampling and convolving functions as Roon, but has a wider variety of filters and modulators.
I described my view of HQ Player in this thread.
I’d suggest starting with upsampling in the Roon DSP Engine, and if you like what it does, then looking at HQ Player.