This is not a update on the eruption. There has not been any major change in the eruption at the writing of this article.
University of Iceland has released a report that can be read here (pdf) showing that the magma that is now erupting comes from the depth of 17 to 20 km. Crust at this location on the Reykjanes peninsula is around 17 km deep. A 3D map can be found here of the eruption. I think it is going to updated regularly by ÍSOR. The lava that is now erupting is part of Tholeiitic magma (Wikipedia). The lava is 1180C when it erupts from the ground.
What seems to be now happening is that a shield volcano is forming. It is a question if this is going to result in a formation of new magma chambers along the dyke where it formed. There is continued risk that new vents and fissures eruptions opens in this change can happen without warning. Based on earthquake activity it seems that the dyke continues to be active rather than having turned into rock by cooling.
It is now estimated that the Geldingadalir valley is going to overflow in 8 to 18 days and currently a lava pond is forming at this location. Once that happens the lava is going to flow into nearby valley (I can’t find the name of it). One of the valley the lava is in the end going to flow into Nátthagi valley if the eruption lasts long enough.