Problem with Hold to Talk on WeChat/ iPhone 6

I am using an iPhone 6 (iOS 8.1.2) and app called WeChat (version: 6.0.1). I am having a problem using the future called “Hold to Talk” on WeChat. It only allows me talk for 10 seconds each time, not the 60 seconds it used to. I didn't have any problems when I used an iPhone 4. I don't have the same problem when I use WeChat on an iPad.

I tried to delete and download WeChat from App Store a few times, but this issue was not solved.

If you could please give me any advice it would be greatly appreciated? 😟