Problem with updaye 5.1.6

I use an iphone 5s and have many problems since the new update...
When i send message, they are loading and loading and loading...(i use a wifi who is working perfeclty fine). So i turn off the wifi, and turn on, and they finally sent. BUT....i reveived a message from my friend, but when i click in our conversation..nothing new...i still see only my message and even unread....please change this as soon as possible T.T

Riiko001 about KakaoTalk, v5.1.6