We reported, a few days ago, that Skype on the Fast Insider Preview ring got an update that allows you to use it as the default app for SMS and regular messages. Now, this feature has been pushed to the Release Preview ring, as noted by Windows Central.
SMS Relay allows you to use Skype as the default SMS and MMS app for your phone. It has been available for a while on the Fast ring in testing and now seems to be on its way to everyone running the Anniversary Update.
We tested it out and it seems to work pretty well with some minor issues like not being able to remove a conversation and some tasks requiring you to go to the normal Messaging app and doing it from there. We've also experienced a problem where sending SMS wouldn't work for a while after a reboot.
Overall, it is a sweet update and welcome change. The feature is expected to come to Android too.