The Last Ring Home
We are not sure of the release date for The Last Ring Home. It was released at the box office on 2016-09-05 so we estimate it was released to DVD in December 2016.
The Last Ring Home is a made-for-TV documentary that recounts the story of how a WWII hero's last wish was lost, found, finally fulfilled and then lost again. The discovery of the story by the hero's grandson is as big as the discovery of the ring.