Wm notes 1.15.0

Pinging @mglukhovsky (and @larkost if he wants to check my checking on pull requests and issues).
As @timmaxw said, this came out of a conversation with @Tryneus -- the only practical impact of this was that logs were being displayed incorrectly in the web UI. As general principle, release notes should address the pragmatic impact of the change, and add detail on the implementation only if it improves clarity / the message.