Re: How do I root the Samsung S5 Active on AT&T G870A?
I'm going to assume (hopefully incorrectly) that rooting the Samsung S5 Active on AT&T is completely locked down/impossible like it is on the Galaxy S5 AT&T.
5.1.1 is rolling out now for S5 Active and Galaxy S5 on AT&T, while we'll see Marshmallow sometime next year.