When my new HTC One DE arrived the other day I removed the SIM from my HTC One X that was already on AT&Ts network with a 4GLTE data plan, and inserted it in the HTC One.. The HTC One worked fine of course and now shows on my account, replacing the HTC One X. My question is, since I had about a year remaining on my contract before the HTC One X would be upgradeable, did replacing it with the HTC One DE cause them to "release" the IMEI for the One X from contractual obligation so I can sell it on eBay? I guess I could call them and ask, but I wanted to see how others plan to sell contract phones they replaced with the HTC One. I did not register in time for the $100 trade up program and anyway, I can get far more than $100 for it on ebay. I just want to make sure it is a "clean" IMEI number so the new buyer won't have any issues putting the device on AT&Ts network.