Microsoft has started rolling out an updated version of Skype (version 8) for the desktop that replaces the classic Skype (version 7). They have also announced that the classic version of Skype will stop working after 1st September 2018 and only the Skype 8 will work.
So, if you are using Skype and in the old version, upgrade to the latest version of Skype for the desktop to avoid any inconvenience once it reaches the end of support.