Max Sockets?

So, I found a Belly of the Beast and it seems to be limited to 5 sockets -- attempting to use a Jeweller's Orb on it gives a message of "Item already has the maximum number of Sockets.

And this matchs what the wiki says for an item with an item level under 50 -- yet I see plenty of 6 socket Bellies on poe.trade, over two hundred of them in the Harbinger league. All of them under item level 50. Can someone explain this to me?

Vorici bypasses ivl.

Ahh.. I did not know that. Thanks.