Connections seems to use CKEditor 4, but in a pretty old version. "CKEDITOR.version" prints "188.8.131.52". We've to scroll on page 3 of the release notes (Don't be confused by the page url parameter, it's index based so page 2 is actually 3) to see version 4.6.2, which was released on janary in 2017. So it's nearly two years old.
In the meantime, several new versions got released. Updating the editor can improve the user experience, since new features got added and some bugfixes were done.