Where is the update for photoshop Lightroom CC 2015 for pictures from Sonys RX10II in raw, named *.arw?
You need to update Lightroom from Creative Cloud.
As the Camera Sony RX10 II is supported in Camera Raw 9.1.1, Lightroom 2015.1.1, so please update Lightroom from Creative Cloud.
Launch Creative cloud and go to the Apps tab. Wait for everything to refresh and then install the Lightroom update. If no update is shown launch Lightroom and try from the menu:
Help >> Updates