I am also having friends complain that they receive my messages more than once. Sometimes my phone will also repeat a message sent from hours earlier or from the day before. I won't even be having a conversation with that person and it just randomly sends text to that person I texted from the day before.
I tried *228 to update my phone but it hasn't helped.
I know how frustrating it can be to get duplicate messages, as it has happened to me too! It's most commonly a temporary issue, however continual concerns with this can caused by many variables like apps, software, network provisioning and more. I recommend erasing the entire messaging conversation then power cycling the phone. If the issue persists, its best to contact us directly or you can message me for assistance.