This is old and it has still not been confirmed. io9 cited an article written by Varitey 2 months ago (not one of their own sources) whom of which cited HitFlix (again, not there own sources). So lets just set the record straight and say that this is for now still an unconfirmed rumour.
So in summation the rumour which io9 is reporting today, is the same rumour from the same sources 2 months back. Until WB releases an official press release, nothing has been "confirmed".
Edit- I see you have removed the words confirmed from the sub heading an article. Next time at least do a little bit of research as to where these rumours are perpetuating before making such silly statements as "Jason Mamoa confirmed to play Aquaman".
Also like I already stated io9, CBR and Variety have all cited the one single rumour from 2 months back which you have already reported here making this article completely redundant. The whole thing just absolutely reeks of clickbait and poor journalism.