Good approach, imho: if it ain’t broke, don’t fix it 
However (sorry for my multiple edits above) it seems to be the fundamental implementation of the library, rather than a specific version, that seems to have caused the problem.
Presentation of the Plex Media Server high CPU behaviour, with minupnd operating in UPnP on the LAN, seems to correlate directly with the change in PMS to utilise the cpp-netlib URI library, likely as part of the “(SSDP) Better checking for invalid IP addresses in location field of SSDP XML” fix in 5488.
