$ sudo apt-get update
$ sudo apt-get install libupnp4 

libupnp4 is installed in your system.

Make ensure the libupnp4 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libupnp4 *

You will get with libupnp4 package name, version, architecture and description in a table

libupnp4 package basic information: