Updare to 7.0.1

Solution
If that option is not in the phone's "Settings" as an update, then there is no 'update' for your device. The only way to change to another version of Android would then be to root the device, which I would not ever recommend. You can easily brick the device in doing so.
If that option is not in the phone's "Settings" as an update, then there is no 'update' for your device. The only way to change to another version of Android would then be to root the device, which I would not ever recommend. You can easily brick the device in doing so.
 
Solution