Don't think this is an easy answer. Skype has been killing off old versions (such as the beloved 188.8.131.52 and 184.108.40.206) and forcing new versions. Most of the "old version" websites that used to host the old install files have completely stopped hosting Skype - my best guess is that Microsoft forced these sites to link to the newest version. Sites that no longer host the download files are:
- FileHippo (all the download links fail)
- OldVersion (download gets redirected to homepage)
- Oldapps.com (there is a notice at the top that Skype is not available anymore)
- CNET (download gets redirected to skype homepage)
- Oldware.org (all versions are 3.0 or less, and cannot sign in properly)
- FileHorse.com (download gets redirected to homepage)
I am looking for a working version of Skype 4 or 5... because 6 and 7 are atrocious. If anyone has an idea where to download the best, most bug-free working version, please let us know!
UPDATE: I found and tried various versions, 5 and below. I can confirm that all versions less than 6.0, and according to Alejandro below, versions 6.6 and below will no longer work. I have successfully installed version 220.127.116.11 from this reddit link, the last version before the interface was completely botched.