Install xorg-server-source-hwe-16.04 by entering the following commands in the terminal:
sudo apt update sudo apt install xorg-server-source-hwe-16.04
Description:
Transitional package for xorg-server-source-hwe-16.04
This is used for upgrading from 16.04 to 18.04.
Version: 3:14.1
Section: universe/oldlibs