HTC devices usually come with Security-ON or S-ON, which prevents you from changing the Cellular ID (CID) or Model ID (MID) of your device, flash OTA updates manually and many other things. To put this more simply, if you are the kind of guy who likes to tinker with their phones, you will need Security-OFF or S-OFF. Going S-OFF won’t change anything from the user-perspective, you will still have the stable device you had before and you will get OTAs like before. Also, don’t confuse this with rooting or unlocking your bootloader, those are separate things. For example, my HTC One is S-OFF with locked bootloader and no root. I get official OTAs without any trouble. S-OFF is required when I convert my AT&T HTC One to Google Play Edition or Developer Edition. Follow the following steps to get your device S-OFF.
Who doesn’t hate carrier branding of beautiful and powerful devices? Carriers actually cripple the full potentials of the phones/devices and make unnecessary delays in getting software updates. So, if you have a SIM-unlocked AT&T HTC One (or T-Mobile version) outside USA, chances are you are not getting the OS upgrades in time, even not at all. Sure, there are ways to flash the update manually (OTA.zip ir RUU file), but how about turning your phone into the HTC One Developer Edition, which ensures updates directly from HTC and lesser carrier bloats? Moreover, the developer edition is one of the very firsts to get any software updates. There are some extra settings (such as, ability to select GSM/WCDMA/LTE radio) in the developer edition. So lets get our hands dirty and turn our beloved AT&T HTC One into HTC One Developer Edition.