So you're telling me I have to call AT&T and request for a sim unlock of my fully paid iPhone 6s that I purchased from the Apple Store? I don't get it I wish I had a T-Mobile nano sim to test it out with. I am reading mixed reviews on the forums.
If you want to get the message saying it's unlocked, back it up to iTunes and restore the phone. Once it's restored the message will appear, then set it back up as your phone from the backup you did earlier. I did this today because I was unsure myself. I purchased a att 6s paid in full from Apple on launch day and set it up thru iCloud. I didn't see a message when I connected to iTunes initially. The only way to see it is to restore the phone