Hi all, My friend has an S5 with a problem that I didn’t know existed. The text program that he uses is the stock Samsung messages. I have a running conversation thread with my friend. This morning, I started getting texts on my S10 from my friend’s S5. In the thread with my friend, from another person. I know for a fact that the person was not him. They tried to say that they were my friend but I know from the way that they talked that it wasn’t him. He also verified that he did not write the texts. My friend can indeed still send texts in that same thread still but so can the third person. We almost certainly know the third person and they live a few thousand miles away, so they have not had his phone. How is it possible for a third person to infiltrate their way into a stock texting app thread and is there anything short of trashing the phone that we can do? Thanks for any help.