No Higurashi Season 3 but another OVA

Against our hopes the next Higurashi series will be only an OVA called "Higurashi no Naku Koro ni Rei"
The OVA is based on the fangame wich has the same name released back in december 2006.
The info comes from the June issue of Megami Magazine.

source:
Moetron
Moonphase