It's best to link to the abstract http://arxiv.org/abs/1605.07969 which will display versions of the paper as it's updated.
My preference is to just read the article. Given the decay rate of Hacker News submissions, it is probably rare for an academic article to see an update during the time it is receiving attention.
Anyway, the original submission has the abstract.
(Submitted on 25 May 2016 (v1),
last revised 26 May 2016 (this version, v2))
>Given the decay rate of Hacker News submissions
but some use the archives