Install Skype for Linux PPA

Create the source list file

echo "deb [arch=amd64] https://repo.skype.com/deb stable main" > /etc/apt/sources.list.d/skype-stable.list

Add public key

wget -O - https://repo.skype.com/data/SKYPE-GPG-KEY | sudo apt-key add -

Update and Install

apt-get update && apt-get install skypeforlinux

The installation also updates or recreates the source list file skype-stable.list.