Microsoft wants to make sure your Skype use isn’t disrupted. The tech company announced that it will “retire” older versions of Skype for Mac (versions 6.14 and under) and Windows (6.13 and under) pretty soon. They did not specify what they meant by retiring but they just want to emphasize that updating now will prevent any disruption for the users in the future.
If that isn’t enough to make you want to upgrade, the new versions of Skype have features like free group video calls and cross-platform messaging. It might be best you listen to Microsoft and update your desktop app now.