I sold my old iPhone and it says “offline” will texts messages still show up in it? I sold my old iPhone to my boyfriends ex girlfriend, I think I went in settings and reset all content and settings. 
Will my old texts still be on it? And could it still be receiving my text and iMessages?
On “find my iPhone” the device is on the list, but it says “offline” does that mean I didn’t wipe it correctly and all my old texts and pictures and everything are still on it for her to go through?
Change your AppleID/iCloud password, that way if the account is still on the device it would ask for a password and become disabled.