For those who have joined the Windows 10 Anniversary Update, and who use Skype there is a new update in the Store. Build 22.214.171.124 is now live for both Windows 10 Mobile and PC up from the previous build of 11.7.87 released on July 27.
No changelog is accompanying this release, and a cursory comparison between the two versions on our phones do not reveal any new distinct features. There are, however, likely bug fixes and optimizations for voice and video calls that we do not see just yet.
If you do happen to find something new let us know in comments and we'll try to verify. Skype UWP is currently only for those in the Windows Insider program.