I got a new S7 phone back in June. Since an update in August the blue LED no longer works when I receive an sms - I use the default app. The LED works fine for Facebook messenger and Whatsapp. I don't know if it works for missed calls as I haven't had any since the update. I also used to get a blue light for other app notifications such as Outlook. I have tried cache clearing, restarting, turning completely off, resetting apps to default, turning LED indicator off and on again as well as off and on either side of a restart. Is this just a bug in the update or is there a setting somewhere I'm missing?
