Git commits in Moodle 3.6.4 by Peter

commit 3a7b1b4d6e54d0dac45270a6877e0f65cf6e7bd7
Author: Peter <peter@moodle.com>
Date:   Fri, 12 Apr 2019 12:45:39 +0800
Tag:    v3.6.4

MDL-65134 core_message: Rerender the message with the updated last msg