I had a problem with the app on the Fantasy this past May. I am not sure if it was just me, but I wanted to red-flag it just in case:
The app, on more than one occasion, would lose its connection between my iPhone 6 and my 13-y.o. son's iPhone 6. The problem was you couldn't tell it had happened. I would text my son and not hear back from him for hours. That's not like him, so I was concerned. Once I found him, we took a look at his phone and saw that my message never reached him. However, there was nothing on my phone to indicate that my message wasn't received, either.
So I thought my message went through, but it didn't. He had no idea I was trying to reach him and thus didn't reply. That was a problem. Once we killed and restarted the app on both phones, things worked again. However, this problem reoccurred several times.