[DopeWeasel]

This works fine for me (TMOUS stock ROM)

This option is under Settings/All Settings/Personal/Voice Command...

Change Notifications to "Announce notifications using Bluetoth hands free if available" and make sure that "Only during free time" is unchecked (unless you don't want it to interrupt your meetings with voice announcements)

Also, look at the options with "Messaging" selected and uncheck "High priority messages only", otherwise it will only announce messages with a High Priority flag.