As integration was developed based on older version, I suggest you to test if it works with 3CX Phone System version 15.5.
Also, you could ask other partners. Might be they have customers using this version.
This is not the issue of upgrade SERP. But serverip.dat in this case contains the value: 192.168.88.12:1301, so this is local IP of the server with SERP.
Anyway I don't understand what do you me...
