Check out this list of cameras supported by Lightroom and Camera Raw to determine which version you need. When you find your camera model listed, make sure you have at least that version of Lightroom. If your camera is not in the list then it isn't supported yet and it will be necessary for you to wait for another update of Lightroom.
Thank you very much. I am just download the right version :-)
In fact, only the very latest version of Lightroom (5.7.1) includes raw support for the A7 II.