Pamela's software still relies on the Desktop API. The Desktop API was officially discontinued years ago and currently only exists in
Skype 7.x (to be discontinued September 1st, 2018). Developers were well aware of this and were encouraged to relay this to their customers. Parts of the API were depreciated, which I have no doubt, stopped a lot of abuse of the API and allowed it still
to work for recording and some hardware. To continue to have a working product, developers would really have to create a solution that does not utilize the API. Since it was discontinued, I am not surprised that there would be no plans, that I know of, to
incorporate it into any newer versions of Skype. I know Evaer and Talkhelper appear to offer solutions that do not rely on the Desktop API. I have no idea why Pamela chooses not to make an updated version for their customers.
Call recording is an option coming to Skype 8.x, so that may be a solution for you. The current insider/pre-release of Skype 8.x already has that feature available and working.