NGINX Plus for Debian 9 - PingIntelligence for APIs - 4.4

# printf "deb https://plus-pkgs.nginx.com/debian `lsb_release -cs` nginx-plus\n" | sudo tee /etc/apt/sources.list.d/nginx-plus.list
# sudo wget -q -O /etc/apt/apt.conf.d/90nginx https://cs.nginx.com/static/files/90nginx
# sudo apt-get update

1. Check whether 19-1~stretch is available in the list

   # sudo apt-cache show nginx-plus | grep "Version"

2. Install NGINX Plus and related modules:

   # sudo apt-get install nginx-plus=19-1~stretch
   # sudo apt-get install nginx-plus-module-ndk=19+0.3.0-1~stretch
   # sudo apt-get install nginx-plus-module-lua=19+0.10.15-1~stretch