If you bought it on Apple up the Apple store will swap it out if you need to switch to Verizon or Sprint anytime while your in the program. Its stated very clear in the terms. People are way over blowing CDMA. Its a very old tech that some rural parts of maybe China use. All the LTE/GSM bands are the same and both are world phones. Ive traveled mostly in Asia with non CDMA phones and had no issues.