I got a response from Promise Support.
The Promose Utility that works with the Pegasus2 R2+ is still not compatible with Mas OS Catalina (10.15). Their suggestion is to not upgrade to Catalina until the new utility is available. But they also do not have an esitmate of when this will be.
Catalina was released in October 2019. The Pegasus2 R2+ is still a current product. If it has not been done in 8 months, it would not be unreasonable to presume that it may not be happening.
Just so others are aware, I used the 'Check For Updates' feature within the Promose Utility - that resulted in the Utility updating to a newer version that does not seem to be compatible with the Pegasus2 R2+. It resulted in a frozen system, and I had to install an earlier version of the Promise Utility. So, I suggest not using that built-in feature. Only download from the correspoding product page on their website.
If you have already upgraded to Catalina, unsure what they suggest.