An instructor asked about the behavior documented here: How do I send a message to all course users in Conversations?, specifically "By default, the Send individual messages checkbox will be selected and cannot be deselected for courses with over 100 students."
He noted that in his previous large-enrollment courses he didn't see this - his messages weren't sent individually. I took a look at his Sent messages and can confirm that up to April 2015 he was sending messages to 174 students in his course and the message sent as one bulk, but as of May 2015 his messages were sent individually. I was digging around the Release Notes for something documenting this change that I could provide to him (he wants to know why) but I couldn't find anything. Am I missing something? Thanks!