User blog comment:Rappy 4187/Technical Update: January 11, 2016/@comment-30384903-20160112165533/@comment-126761-20160113153614

This didn't get mentioned as it was intended to be essentially invisible, and the resulting bug only affected a niche set of users. The fix is live now :)

That said, these posts are definitely the best place to look for that kind of update info.