So the problem is that I have an iPhone5 from my cousin, and yesterday I got a messages in WhatsApp from friends but I couldn't open WhatsApp. It said that I need to update WhatsApp. I went to the App Store and it required the password of iTunes Store but old email and password from my cousin, and I don't know the password.
Does someone have a solution for this? I also don't want to delete my WhatsApp because I cannot backup my chat history and also will not see the new messages that come in my WhatsApp.