I have HTC ONE DUAL SIM 802D. It's running Android 4.4.2 with Sense version 6. But I'm unable to get any more updates. Whenever I check for updates in the settings, it just keeps on checking and doesn't even tell that your phone is up to date. When I got the phone it was rooted but bootloader was locked. Now I have unrooted the device, still the same problem persists. Kindly help.