In August, Microsoft announced a major refresh for its Skype desktop application, following suit from its mobile app redesigns earlier this year. The new app is coming out of beta today, and it's available for Windows 7, 8, and Windows 10 versions 1511 and earlier.
The reason that it's not available for newer versions of Windows 10 is because Microsoft introduced a UWP Skype app in version 1607, and that's what the company wants people to use moving forward. In fact, without a workaround, this new Skype desktop app will be the first that won't install on newer versions of Windows 10.
The most obvious change that you'll see is customizable themes. You can choose between light and dark, and you can also pick a color scheme. There are also some improvements to the chat list. You can sort it in different ways, and you can change the view from standard to compact to see more of the screen.
There's also a notification panel inside of the app, which you're probably already familiar with if you've been using the mobile app. You can use this to see reactions to your messages, @-mentions, and more. Of course, reactions and @-mentions are new as well.
The update isn't live for Windows just yet, but it should be coming later on today, either by automatic update or manual install from Skype.com.