If you manage to find and install this version, here is what you can expect compared to today's software:
Around the time of version 6.0, Skype (under Microsoft) began shifting away from pure P2P toward a centralized "Supernode" architecture. This transition was controversial among purists but laid the groundwork for the reliable, server-based messaging systems we use today in Skype and Microsoft Teams. skype 6.0 download