This video is worth a watch:
In the video info there are links to older version of skype that are patched to make it work in 2016.
v5.5
https://drive.google.com/file/d/0B0Q...ew?usp=sharing
v4.2
https://drive.google.com/file/d/0B0Q...ew?usp=sharing
v3.8
https://drive.google.com/open?id=0B0...jkzTmZCMWxwdzg
I just downloaded 4.2 and seems to work fine.
All old skype versions are available here : http://www.oldversion.com/windows/skype/