Last week when Microsoft released build 14342 they said that the Skype Preview app had been updated in the build, with them later updating the blog posts saying the update is coming soon (after I spent some time looking for the changes!).
Well the app has finally been updated and includes Windows 10’s dark theme support and multiple account support so you can switch between Skype accounts. The dark theme is actually a nice dark blue colour which I rather like. The app is updated via the Windows Store and is actually listed as “Get Skype” in the store update screen.