From the abstract of the Nature paper:

"Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere."

Emphasis on "cool enough to support" (not supports) and "probably been" (not has), and "will be able to observe" (not has observed).

http://news.mit.edu/2015/new-earth-sized-exoplanet-1111

https://en.wikipedia.org/wiki/Gliese_1132_b

http://www.nature.com/nature/journal/v527/n7577/full/nature1...

edit

Not exactly replenishment, water gets broken up into H and O, some of the H streams off into space, leaving stray Os floating around. In that case everything is just slowly boiling away into space.

@greeneggs is correct[0], that article is talking about modeling of a hypothetical atmosphere for a given planet. There was not an actual detection of oxygen in the atmosphere.

[0] https://news.ycombinator.com/item?id=13700744