Why is my group message option unavailable?

Hello guys,

i recently bought iphone 6 from a person, at that time it had ios 8.1.1,

in settings i saw there was group message option available, i then updated it to ios 8.1.2, now the problem is this that it doesn't have group message options available in message settings. so it doesn't send messages to multiple now.

i m extremely upset due to this unavailability, plz help.

Have you tried rebooting the device ?

I have ios 8.4 in IPhone 5s
I had the same problem and tried everything but Resetting the Network setting did the trick for me