[Q] Question: Lastest android version/rom and Sense for my HTC One M7 topic

Hi!
I have an HTC One M7, which has an AT&T logo on the back, but it works with all the carriers.
Here are my questions:
What are the lastest Android and Sense versions for the HTC ONE M7?
Where can i download the official versions of these updates?
Since my HTC is unlocked but it has an AT&T logo in the back, should i install the versions for Unlocked phones or fot AT&T ones? I don't want to brick it.

Thanks in advance.