Thanks for your prompt response Alex. I agree with your suggestion. I nonetheless attempted 16.04 libjson-c2 installation on my test machine, nimble server installed and is now configured and streaming test is going ok.
Url to libjson repository:
http://archive.ubuntu.com/ubuntu/pool/main/j/json-c/
.deb file for 64bits, saved to Downloads folder:
libjson-c2_0.11-4ubuntu2_amd64.deb
Command line libjson-c2 installation:
sudo apt-get install '/home/username/Downloads/libjson-c2_0.11-4ubuntu2_amd64.deb'
Then standard procedure for Ubuntu 16.04 Xenial Xerus as explained in wmspanel.com
Best regards